by B.B. Pelletier
Announcement: The blog’s server went down on Thursday, April 21, 2011. It came back online Sunday, April 24. This blog was published early Monday, April 25, and is dated Friday, April 22. Monday’s regular blog will be published in the afternoon of Monday, April 25.
This is a good, long report, so grab your coffee and perhaps another Danish. Today, we’ll learn something about accuracy and group sizes.
I’m testing the accuracy of the .22 caliber BSA Scorpion PCP air rifle, and it’s quite nice! Helping quite a bit was the weather at the range, which was perfect for long-range airgunning, as there wasn’t a breath of wind to be felt. The day was overcast and misting slightly and with every shot you could see vapor at the muzzle when the compressed air emerged.
I scoped the Scorpion with a CenterPoint 8-32x56AO scope that was sharp and clear. Even though I shot at the small 50-foot rimfire bulls like I usually do, they appeared quite large and sharp through the scope. I was easily able to bisect the center ring with the crosshairs.
I had filled my carbon fiber air tank since the velocity test, so I was able to fill the rifle up to its maximum of 232 bar. I couldn’t do that in Part 2 because my tank was below 232 bar, so I’m going to give you a second look at velocity today, with some of the pellets I used for accuracy.
Accuracy first
The gun was not sighted-in because I had just mounted the scope the evening before. Normally, I like to shoot the first few rounds at 10 feet to adjust the scope on target at 20 yards, but today I did something different. I stapled a huge silhouette target to the target frame, then put my targets on that. That way, I had two feet by four feet of paper for the pellet to hit. You could also use a large piece of butcher paper or even cardboard to do the same thing. So long as there are no holes in the paper when you start, just attach your real target to the center of the larger paper and start shooting. For those of you who shoot at public ranges where you cannot put your own target on the range at different distances, this is a handy trick to avoid boresighting.
The first pellet I tried was the 18.1-grain JSB Exact Jumbo Heavy pellet that everyone raves about for powerful PCPs. Since this rifle is capable of almost 40 foot-pounds, it seemed perfect for that pellet.
The first five shots were barely on paper, but they did strike the intended target paper of 11 bulls. Though they all landed in the upper right corner of the paper, I scanned the group to show you how the gun did. Bear in mind that this is only a five-shot group, and it not representative of the true accuracy this rifle can offer, but it’s in the ballpark.
The first five shots from the BSA Scorpion at 50 yards made this 0.175-inch group! Now, that’s a screamer, folks! But look to the upper right of that hole and you’ll see another partial hole. That was shot No. 6. And THAT is the reason that 5-shot groups are not enough. Read the text for the explanation.
Okay, I hope you’re as excited as I am by this first group. All five pellets wanted to go to the same place. I’ve tested accurized Ruger 10-22 target rifles that did not give results as good as this. However, as I indicate in the caption, shot No. 6 landed apart from the group. Since I have a little experience with these high-pressure, powerful BSA rifles, I suspected what was happening. I quit shooting this group and adjusted the scope. Because this rifle is advertised as having 20 powerful shots on a fill, I continued shooting after adjusting the scope.
This is the telling target. There are 10 shots here, but they represent shots number 7 through 17 on the first fill. The same JSB Exact Jumbo 18.1-grain pellet was used. Notice the two definite groups we have. The upper group contains the first six pellets and the lower group the final four. This rifle is losing pressure and changing the point of impact as it does! That is why the sixth shot in the first group was apart from the other five. This whole group measures 1.013 inches but the top group of six measures 0.533 inches.
I’ve seen performance like this before in these 232-bar BSA rifles. They have a large number of shots for the relatively small reservoir on the gun, but the valve cannot perform with stability across the entire fill. You do get 20 powerful shots, but the POI will change slightly as the pressure diminishes. Hunters may not notice it, but it shows up clearly on paper at 50 yards. I decided that with the 18.1-grain JSB Exact Jumbo pellet the Scorpion had only five good 50-yard shots on a fresh fill before it started to shift POI. I refilled the rifle and shot another 10-shot group to see if that was correct.
Here’s the proof of what I’m saying. The first five JSB Exact Jumbos stayed in a very tight group, but starting with shot No. 6 the group spread laterally to the right. The last shot went to the far left, so the POI was still shifting. The group measures 1.49 inches between the two widest centers.
What does this mean?
All is not lost, nor has the sky fallen. You have a choice when presented with this type of performance. Either refill the rifle after every five shots and get bragging-sized groups at 50 yards, or accept the 10-shot groups that you do get and continue to shoot this pellet, or find a different pellet.
The weight of the pellet, plus how it fits in the bore, determines the dwell time that the pellet remains in the barrel. For most of that time, the back-pressure of air inside the barrel behind the pellet holds the firing valve open and air escapes. Changing to either a lighter pellet or one that fits looser — or both — will change this relationship and give you different results, as we shall see.
These JSB Jumbos fit the bore so tight that I could feel them pop into the breech as the bolt was closed. So, they’re both heavy and tight.
Next, I tried the Beeman Kodiak copper-plated pellet. They weigh the same as the all-lead Kodiaks, and past testing has shown that they’re equally accurate, so let’s see what they did in the Scorpion.
A beautiful nine-shot group! If only that tenth shot wasn’t in the center of the bull. I don’t know which shot it was, but I do know it was not in the first five, nor was it the last shot. Group measures 1.227 inches between centers, with nine shots in 0.537 inches.
Kodiaks weigh 21+ grains; and like the JSB Jumbos, they also popped into the breech. Well, I decided to try it again because that nine-shot group was a good one. So, the rifle was topped off, and I shot the copper Kodiaks a second time.
This 10-shot group shows more spreading than the first one did. Again, I got a flyer through the center of the bull, but this time there were also two that went to the right. Group measures 1.253 inches between centers, and you can see that the first seven are in a tight bunch in the center.
What next?
Well, at this point I reckoned that I had the Scorpion pretty well figured out. Heavy pellets were going to use a lot of air, which resulted in a change of POI in the middle of a 10-shot group attempt, so they were probably not the best pellets to use for what I was doing. However, if you could top off after five shots, then they would be ideal.
I tried one more pellet just to prove my point about the heavy pellet POI shift after five shots. This last one was the 28.4-grain Eun Jin pellet. If ever a pellet was going to hold open a valve, this is the one that would do it.
Well, it doesn’t get much more obvious than this. The first five are in a tight group that then drops to the right. The final three pellets are on the extreme left. The group measures 1.774 inches between extreme centers and is the largest group of the test. No sense shooting another one.
The results were as clear and unambiguous as they could be. The tendency to spread after five shots continued in a most aggressive way. The central group of five measures 0.526 inches between centers. So, shooting the first five shots from a fill is still a viable option, even with this heavy pellet.
Now where do we go?
Isn’t it obvious? If the rifle can’t shoot heavy, tight pellets more than five times on a fill, what will it do with lighter pellets that are loose? Luckily, I happened to have a tin of the old standby 15.8-grain JSB Exacts on hand. They’re the lightest pellet I tested, and they were loose in the bore.
Ten 15.8-grain JSB Exact pellets went into 0.62 inches at 50 yards. This is almost as good as a custom-tuned 10-22 Ruger I tested years ago. This is a good pellet for the Scorpion.
The first target was good, so I shot a second one. It measured so close to the first one that I cannot discern a difference.
A second group of 10 15.8-grain JSB Exacts measures the same as the first one. This is obviously the pellet for this rifle.
Velocity
I said I would do some more velocity testing for you because I wasn’t able to completely fill the rifle in Part 2 of this report. I’ll test two pellets — the 18.1-grain JSB Exact Jumbo heavy and the 15.8-grain JSB Exact. They should show us what the performance curve looks like, and we can extrapolate to other pellets whether they’re heavy and tight-fitting or light and loose.
The 18.1-grain Exact Jumbos averaged 871 f.p.s. for 20 shots, but the spread went from 818 up to 904. Starting with shot No. 6, the velocity fell off on every successive shot. Shot 15 was still going 848 f.p.s., so for hunting purposes that might be your last shot on a fill. But shot five is the last one for a super-tight group at 50 yards. The first five shots averaged 899 f.p.s., with a muzzle energy for just those five of 32.49 foot-pounds.
The 15.8-grain Exacts averaged 891 f.p.s. for 20 shots with a spread from 810 to 947. Every shot except shot five was a decrease from the shot before, and the rifle dropped velocity faster with this pellet than with the heavier one. Velocity alone doesn’t explain why I got such great 10-shot groups, because by shot 10 the rifle had dropped 45 f.p.s., where the heavier pellet lost only 18 f.p.s. Still, the groups don’t lie. This is the more accurate pellet. The first five shots averaged 936 f.p.s., for a muzzle energy of 30.74 foot-pounds.
Conclusions
I seem to be pushing the 10-shot group a lot for accuracy testing, but today was a perfect example of why it’s better. Yes, this was a very specific situation that you wouldn’t encounter in a spring rifle, but those extra five shots give any gun every chance to express all of its bad traits. A 30-shot group would even be better, but except for extreme product testing or belaboring a point, it’s seldom done. Ten approximates 30 closely enough for most purposes.
Looking at the price of the rifle, it offers a hunter good value in a traditional-looking powerful rifle. The trigger is okay and nothing about the rifle is bothersome, except for the 232-bar fill pressure. The accuracy is stunning, as you have seen. It cracks like a .22 short, so be ready for that. In fact, after I finished the velocity testing, Edith said, “That was loud. What was it?”
I replied, “BSA Polaris.”
But that didn’t sound right, so I thought about it for a second until the name came to me.
“Scorpion!” I shouted a minute later.
“Where!” she answered, running into the room with her shoe off, looking for the arachnid invader.
So, the old girl still has life in her yet.
And, by the way, I can still shoot a rifle, in case anyone asks.
B.B.,
Nice to see you back. You weren’t missed but Edith sure was.
The accuracy of the scorpion doesn’t surprise me. I’ve shot a bsa lonestar quite a bit and the gun has stunning accuracy. Low shot count like the scorpion though. Guess I would put the scorpion in the catagory of a powerful pcp since I don’t like target shooting with air hogs. I’d choose a .25 caliber for this reason too.
Yes, you can still shoot a rifle. All of those 5 shot groups are impressive.
kevin
B.B.
I’m glad this blog is back online. You scared me, you know 🙂
Some good news – weather here is finally spring, it’s +14, warm sun and blue sky.
I started manufacture of the first part of my “duskombe” rifle, the synchro unit, hope it’ll be done soon.
duskwight
duskwight,
Remember to take good pictures, so you can show us all the steps to build your rifle. We are all interested in your progress.
I converted +14 Celcius to Farenheit and it comes out to 57.2 degrees. When it gets that cold here in Texas we throw another log on the fire and break out the long underwear! I like any temperature over 85 F. (29.444 C.). 😉
B.B.
It’s around the same temp here going a bit above 15º (60° F) the pants are all back where they belong (in the closet) and the shorts are out for me, no more long pants until October YAY!!!
J-F
B.B.
You’re one heat-resistant man! I think Texas is a place somewhere on Tatooine 🙂 Frankly, +29 for two weeks is going to kill me, I don’t know how I survived last summer.
If I could rule the weather I’d prefer +23 all the summer, ok, +26 max in July top weather. +18 water is warm enough to swim in fresh or salty water, I think J-F will support me on that and +18 air is really good for shorts, that’s where I heartily support him.
In my experience +20-22 C is the optimal temperature for shooting springers, when your rifle’s powerplant is at optimum performance and you feel nice and cool, able to shoot tens after tens.
duskwight
duskwight
“duskcombe”, I love it. Don’t overlook ‘duskwerkbau’.
Please do take some photos and a complete rundown, once it is built. Your concept has had me intrigued for quite some time.
Slinging Lead
I think FWB guys would be too jealous, he-he-he. In fact “duskwerkbau” were my Mom and Dad 🙂
duskwight
Wulfraed,
Yes, it was Amazon. The airsoft blog & Pyramyd Air’s retail site are located on different servers.
Kevin Lentz posted a comment and a link to an article about the outage on the yellow forum so people would realize it wasn’t their own ISP connection.
Edith
B.B.
Sounds like Edith has not yet fully been “Texanated”. A genuine Texas redneck would have come out with a centerfire. Probably big bore.
twotalon
twotalon,
With all the holes I have put in the walls over the years, she saves the big bore stuff for the yard. 🙂
B.B.
Kevin
Thanks for the belly laugh, you are in rare form this morning.
This is an excellent blog BB, what a treat to come back to after that excruciating hiatus. I got about the same performance out of the JSB 18.1 in my Marauder, except nothing as enticing as that first target you shot! Without your depth of knowledge, If I had shot a group like that I would be forever chasing those same results…fruitlessly, until I ran out of JSB 18.1s. You certainly can shoot a rifle my friend, kudos. I think that rifle is a screamer though, I wonder if they will all be like that.
When you shouted “Scorpion!”, I half expected Edith’s reply to be “Well, just throw it back in the cage with the others.” You have shattered my fantasy of what Texas is like. You do have an oil well out front don’t you?
SL,
In my experience with BSA PCPs, they are all like this. I haven’t shot the R10 or the Super 10 which may be different, but these small-reservoir rifles like the Hornet and the Tech Force clone of the Hornet, both act exactly like the Scorpion.
B.B.
Glad to see you back BB.
Talk about ‘you don’t know what you got till it’s gone’.
I was just going to dip my tiddly’s into the great accuracy debate.
Reading both your reports back to back,they had something very important in common.
Accuracy was better when a particular pellet was shot from a particular gun.
Nothing new,the broad consensus already is that this is the case but it helps make my point.
We all shoot different guns(PCP’s,Springers) at different distances using different calibres.
Despite that,a consensus has been achieved about the importance of finding the right pellet for your gun.
So I reckon it is quite possible to reach a consensus over other matters such as sorting,weighing and lubing pellets for example.
Is your accuracy (Whatever you hold that to be) improved by adopting these measures or not?
I talk a good fight though.I haven’t even got the means to weigh bloody pellets. 🙂
DaveUK
Dave
Have you ever thrown a scope on your HW99 just long enough to determine how accurate it can be? Out of all my airguns, my HW50 is probably the least promising in terms of accuracy judged by the shot cycle. Mine requires a good amount of force to cock and fires very sharply, with a kick on par with Diana’s higher powered springers. Follow through is very difficult for me due to this. Magically when I reopen my eyes, the pellets are stacked or very close together. It is one of my least well behaved, but most accurate rifles. Have you ever considered a tuning kit? I am going to get a Vortek kit for mine eventually. I hear the V-Mach kits made in England are about the best around.
Cheers mate.
Slinging Lead:
No I haven’t tried a scope on my HW50/99 mate.
Firstly,money to be honest.
Getting a good scope and mounts is going to cost over a hundred bucks at least.Almost half what the rifle cost new.
Secondly,need.
As you can attest,the open sights on these rifles are superb.
Do I NEED a scope?
It would be hard to justify bearing in mind the money(or lack of) aspect.
I have no reason to doubt my rifle would perform well with a scope though.
Reading the reviews of the HW50/99 I was expecting the firing cycle to be more harsh than it was.
Maybe I’ve been lucky but mine has been pretty smooth from the start.(Or was it my BAM was so bad anything was an improvement?)lol
While cocking,the last quarter inch was a little tough to begin with but now that’s fine and there is no ‘Twang’, just a gentle reassuring kick when fired.
As far as tuning is concerned ‘if it ain’t broke,don’t fix it’ is probably the best option in my case.
Funny enough it was BB a while back who told me some of the best tuning kits come from the UK.
That did surprise me.
DaveUK
I have a pellet-choice question for anyone with enough experience to answer. We constantly see on this blog that spring guns can be very picky about what pellet they will shoot accurately. This FINALLY got me thinking, and wondering if the same is true for MPP, CO2, or PCP guns? For example, I have a 1377 that shoot CPHP’s better than Daisy Pointed pellets. Is that because one pellet is better than the other, or because the gun prefers the obetter-shooting pellet? Perhaps a better example is that the gun shoots CPHP’s better than the Crosman Competition Wadcutters. Again, is that the gun’s preference or the quality of the pellet.
And, this has probably been addressed before, but can someone tell me WHY spring guns can be pellet picky? Please be as detailed as you can, if you have a good answer.
jmdavis,
My opinion on your pellet questions.
When talking about supreme accuracy, every airgun can and usually is fussy about ammo (pellets). Rimfires are notoriously fussy about ammo.
There’s a lot of speculation as to why but few conclusions. In my experience, domed pellets at distance are typically more accurate than either wadcutters (match pellets), hollowpoints or pointed pellets. Suspect this is because a domed pellet has better aerodynamics.
My definition of a “better pellet” is one that is uniform in head size, has less lead flashing on and in the skirt and is consistent in weight. Using this definition, I would say YES “better pellets” are many times, but not always, the more accurate.
kevin
BB,
I’m curious about why the stringing on the heavier pellets would be so strong horizontally, and not as much vertically? I would expect the pressure drop / velocity drop to be the biggest factor, and that the results would show up more as a vertical stringing.
Any thoughts?
Alan in MI
Alan,
Barrels vibrate in all directions. The loss of a few f.p.s. doesn’t affect grouping vertically, or .22 rimfires wouldn’t be able to group. But when the vibration patterns change, the pellets go everywhere.
B.B.
BB,
Welcome back! It was taking so long to restore your blog that I was worried that the blog got clobbered. Unfortunately when you use a service you’re totally at their mercy for backup and recovery.
– – – – –
RE: “Pushing 10 shot groups”
As far as 5-shot versus 10 shot groups go, it occurred to me that there are different ways to weight mathematical information. As a writer you are certainly striving for creditability. So showing a 10 shot group provides more creditability than showing the group size from a 5-shot groups. However the average of two 5-shot groups will be more repeatable than a single 10-shot group size.
Of course honesty is a big factor here. The two 5-shot targets have to be “representative,” they can’t be for instance the best two out of five 5-shot targets. So if you wanted to average multiple targets then you’d have to spend a lot of time explaining the mathematical setup of the experiment which is very dry reading for most of your readers. If you think about it, even specifying that you shot the two 5-shots targets “in sequence” isn’t enough. Think about shooting 10 targets. Now to select a pair of targets there are 9 choices (1-2, 2-3, … 9-10). The “best” choice is certainly going to be a lot better than the “worse” choice. Such is the perverse nature of statistical based information.
– – – – –
0.62 inches is of course a nice group size for the 15.8-grain JSB Exacts. However getting two groups very close together in size is pure luck. Anyone who expected that kind of consistency would be forever chasing his tail. Without doing any analysis, I’d guess that the 95% Confidence Interval would be something like .3 inches to 1 inch. It would be rare through that a shooter would shoot 100 such targets to see that much variation.
Again, such is the perverse nature of statistical based information.
– – – –
Again, welcome back. I missed reading the column on Friday. I guess I checked twenty times over the weekend worried the numb-numbs destroyed your blog. It was fantastic to see what seems to be a fairly complete recovery.
Herb
PS – Yelling “scorpion” in Texas would seem like a dirty trick. You were lucky Edith didn’t whack you with the shoe. 😉
I “think” I do better with 2 different shootings of 5 shots, rather than one 10 shot shooting. I “think” it is me that causes a 10 shot group to open up. My eyes get tired, I get day dreaming, I hear a TV show I want to watch. If I was to shoot a 100 shot group it would really open up, and I “think” it is mostly me.
Of course me thinking is an oxymarooon. lol
Gene,
BB had another point on this that is absolutely true. The average for an infinite number of 5-shot groups would be smaller than the average of an infinite number of 10 shot groups. See for example:
http://www.the-long-family.com/Group%20size%20statistical%20analysis.pdf
ratio 10-shot to 5-shot = 0.876/0.667 = 1.30
So smaller isn’t “better” in this case. A 10-shot group will on average be 1.30 times as larger as the 5-shot group. Most folks exposure to statistics is the normal distribution, and that is just the wrong model for group size itself. This is just another example of the perverse nature of statistical information.
Regards,
Herb
The other “easy” thing to remember is that the average POI of two 5 shot groups are almost guaranteed to vary at least slightly, often “significantly” (statistically, adjectives are a problem in the world of statistics 🙂 ).
Two “identical” five shot groups, if superimposed on each other with respect to the POA, are almost guaranteed to result in a combined 10 shot group that will be larger than the individual five shot groups.
Alan in MI
Wait just a cotton-pickin Easter moment! This blog was dead on Good Friday and rose again on Easter Sunday?
I just read that a woman named Mrs. Easter won lotto on Good Friday. Neato
God bless her, but I hope she wasn’t already wealthy. I once worked at a country club where a member that was already a millionaire, won the lottery. “Good news, Muffy. We will be able to trade in the yacht this year for a newer model.” (retching sounds ensue.)
I don’t know about the USA but in Britain often the lottery winners don’t want to move house or give up their jobs at the ‘widget’ factory.
What’s the point of winning the lottery,if you aren’t going to tell your boss where to shove it?
So SL, did you cease to work at the country club after you punched ‘Muffy’?lol
DaveUK
I hope this isn’t too much detail. But I thought I’d try to follow alomg with BB’s tests on my 10m range.
4/22/2011
Great Accuracy Test – Using Reading Glasses
GAT – Great Accuracy test
Shooter – nearsighted, left-handed, left eye dominant, Prescription – Left eye -1.25, Right eye -2.00, left eye distance vision has improved with some loss to reading ability since this prescription was issued.
Rifle setup – Bronco, Beeman Aperture Sport peep sight, Screws checked for tightness, JSB Exact RS 7.33gr, pellets are selected from the tin at random, un-weighed, un-sorted. Predator shooting rest, NRA 10m rifle 5 bull target, Sight picture is 6 o’clock hold.
Environment – Indoors 10m range, Temp 68F, Barometer 29.8, and Humidity 50%, was raining outside during test.
Test Method – 5 warm-up shots, 10 shot groups, Reading glasses – tried +2.00 and +1.50
Miscellaneous Comments – I normally use the +1.50 for reading, I tried the +2.00 for reading but they were too strong .
Resulting targets:
https://picasaweb.google.com/cjrley/GATReadingGlasses?authkey=Gv1sRgCLvelK25g4Sheg#5598506003024996818
I shot the group on the top left without any corrective lenses. The front sight is not crisp but not too bad, same for the target bull. The target is more out of focus than the sight post, though. This group has one un-called “flyer”.
Next, I tried the +2.00 reading glasses but didn’t shoot with them because the front sight was reduced to a thinner but unclear image and the target bull was so fuzzy as to not be visible.
On the top right bull I switched to the +1.50 reading glasses and the front sight was still thinner but crisp and the target was smaller but visible, yet still blurry. Everything looked smaller and farther away with the reading glasses on. Notice the vertical stringing on the top right target while using these reading glasses and the two un-called “flyers”. I had difficulty seeing the bottom of the target bull. Not a good sight picture.
The middle target I shot with my regular progressive lens glasses, looking through the top – again with the two un-called “flyers” – and then I shot the bottom left bull with the +1.50 reading glasses again just to have another comparison. There’s those two “flyers” again. I must have had silent hiccups. Notice, no vertical stringing on this second example occurred, though.
One useful thing I noticed is that with the progressive lenses I could move them up and down to vary the focus between the front sight and the target. I think I could have reached a very happy medium for 10m but had no way to hold it there while shooting.
Conclusion
I will conclude that wearing reading glasses definitely did affect my accuracy. However, not in the way I wanted. My reading glasses didn’t help enough to make me want to use them. All I proved is that the harder it is for me to see the less accurate I will be. Hardly earth shattering news. Yet, I wonder if the right prescription could be ground that would allow the front sight to remain crisp without making the bull appear fuzzier than with my unaided eyes? I think it’s possible. Also, the focusing problems I had would probably be very different at 25yds.
Also, I’m counting on the GAT to help me eliminate those pesky “flyers”. I have used quotes on the word flyer because of the controversy over its definition. I couldn’t call them because I couldn’t see the POI well enough to tell if I should have.
-Chuck
Chuck,
What you did is exactly what I was hoping for. We will continue the GAT, only I won’t spend much time explaining my failures. But if something does work, we will all be able to test it.
B.B.
Chuck, some real data points. That’s great.
Matt61
I usually shoot what looks more like ten one shot groups.:-)
Glad your back up and running I was starting to have withdrawal symptoms.
BB,
I noticed that you shot some copper plated pellets. What are the claimed advantages (and disadvantages) of using copper plating?
pete
pete,
Copper-plated pellets have been around for 40 years or so. I think people use them because they are afraid of lead poisoning.
These Baracudas are the first copper-plated pellet I have seen that is accurate. However, if they cost any more than plain lead pellets I wouldn’t buy them.
B.B.
Shucks,
If you wash your hands after shooting and before eating, you’re not going to get lead poisoning. Besides, the body is much more vulnerable to lead compounds (think lead oxide in paints) than to metallic lead.
I guess the copper ones are shiny and pretty, if that matters more than accuracy.
I haven’t tried the copper plated Barcuda’s, but based on my experieince with them in the Beeman FTS pellets, I’m in no hurry. I can’t explain why, but the copper coated FTS don’t do as well as the plain lead FTS in any of my .22’s, despite the fact that the lead FTS (and H&N FTT) are among the best in the same guns . . . .
Alan in MI
That was a new one to have the blog offline for three days. But I see we haven’t missed a beat and all the missing material is posted. Between that and the comments is almost too much to respond to. Regarding today’s accuracy test, I would say…those are mighty impressive groups.
Regarding the previous post on reading glasses and sorted pellets, I would venture to say that we are dealing with a few too many variables some of which seem to be linked. I think it might help to clarify why reading glasses would or would not be helpful. My guess is that first it depends on the prescription of the shooter. Assuming that reading glasses would benefit the shooter, I guess they would operate by allowing a clearer picture of the front sight which you are supposed to be focusing on anyway. So, it makes sense that they would help if you would benefit from reading glasses at all. Also consider laser surgery. I’m like a new man since I had it done.
FrankB, very germane question about where to put the front post for the 6 o’clock hold. The best answer I’ve seen comes from PeteZ’s reference to the great Russian shooter A.A. Yuryev. The thinking is that if you hold so that the post just touches the bottom of the bull, you cannot really tell if you are overlapping the bull by a little bit. So, instead you want to keep the smallest possible amount of white space between the top of the post and the bottom of the bull. Of course it is hard to measure the correct amount of white space and this is a source of variability, but trying to minimize this white space is the best option. It worked well for me, and I am a convert.
Herb and PeteZ thanks for your thoughts on evaluating group sizes with different distributions of shots within the same area. I think I understand your solutions. Upon further reflection, I thought that you could construct the characteristic standard deviation for each and use that with the usual z-score to figure out which shots fall within the 95% confidence interval. But that doesn’t answer the question of why one group should be shaped differently than the other (assuming the same gun and conditions) or whether one is “better” than the other.
Duskwight, that’s some great info about Russian snipers. I do believe that the Soviet PU scope with the three line reticle and 3.5 power seems to be close to the red dot scopes of today which is to say quick target acquisition and relatively low power. I tend to agree with the view that the Russians have been in the forefront of sniper development in the 20th century. They had a much larger supply of trained snipers in WWII than anyone else. And their development of the Dragunov in the post-war era was also ahead of its time. Laughed at as inaccurate by precision snipers, it anticipated the belated move to designated marksmen and semiauto snipers that the U.S. military is moving to only now. On the other hand, I don’t know if Russia has settled on a precision sniper design. One that they worked on, apparently was not satisfactory. However, I’m sure a nation that does so well in Olympic shooting will have no problem coming up with a very good design. So, Duskwight, tell us some Russianisms from the film Enemy at the Gates. 🙂 I read one from after-action reports by German generals after the war. They said that their Russian opponents would sometimes make tactical decisions that seemed to make no sense, but as the battle unfolded turned out to be the exact right thing to do.
While away from the blog, I came across a statistical distribution of accuracy for surplus Lee-Enfield rifles. It wasn’t too good. Average accuracy was 4 MOA with some better or worse according to a normal distribution?!
Much as many of us might dislike statistics, the fact is they are all around us and liable to bite us at any time. I am doing a project at work for which we are supposed to have the services of a professional statistician. Well, between his inconvenient work hours and habit of not answering email he is useless for an upcoming presentation. My fellow researcher doesn’t know anything about this. So, if it is going to get done–and it has to–it looks like it’s up to…. I’ve been at it after hours trying to make sense of a textbook on a bivariate analysis for comparing two groups. Argh.
Matt61
Matt,
Don’t know that I can help with your work problem, but the nature of group size has some unexpected characteristics. Like the Poisson Distribution, the average value of the group size and its “standard deviation” depend on a single measured parameter, the average group size. In other words, you can calculate an “estimated standard deviation” from the measured group size! There is a different “fudge factor” depending on how many shots in a group. So the effort is to get a good average group size.
Thus neither the Z-test nor the T-test really apply to group sizes. the application is particularly bad for small number of shots in a group, or a small number of groups. The paper by Taylor and Grubbs gives the data for a single measurement of group size, but I don’t know of any tables that combine multiple measurements. A couple of examples where combined tables would be helpful:
* Given that the average group size of two 5-shots groups is 0.8 inches, then what is the expected variation of the average?
* Given that the average of ten 5-shots groups is 0.83 inches, then what is the 95% confidence interval for subsequent (individual) 5-shots groups?
If I had ten measurements then I could calculate the standard deviation of the ten. But the standard deviation of a sample is much less precise than the average. So the “calculated standard deviation” of the sample is less precise that the “estimated standard deviation” found using the average group size and the fudge factor for the number of shots in a group. So if the “calculated standard deviation” is larger than the “estimated standard deviation” then (1) either the assumptions about group size are wrong, or (2) you have flyers.
Group size is truly an odd-ball statistics. I have been looking and not be able to find a good set of tables of combined data. I’m really curious as to what tables Grubbs had in his work “Statistical measures of accuracy for riflemen and missile engineers.”
Herb
Matt
Just some simple facts I remember myself:
1. Nobody crossed Volga in daylight – it was a suicide because of Stukas (and Annaud is very correct on that 🙂 ). All the movement across the river was made during the night.
2. Nobody guarded soldiers as if they were convicts.
3. Zaytsev was NOT a conscript. He was rank-and-file Marine from Pacific fleet, serving since 1938, in the rank of mate.
4. No troubles with rifles – every soldier was armed on Eastern side of the river, and supplied at least 120 rounds. During war, when Soviet economy recovered a bit after shock of summer-fall 1941, even penal squads had enough rifles, ammo and grenades to do the job. Another story is that their job required something more than rifles and grenades 🙁
5. I understand that bloody Soviet regime sent people into grinder, but they didn’t even give them belts to beat Germans (in case they were left without rifles), cantines to carry vodka, helmets to seat on, ammunition pouches (yes, yes, I know, no rifles – no ammo) and other unnecessary stuff. Despite that, Hitler’s troops are excellent-equipped.
6. I do pity poor German sniper played by Ed Harris – he was wearing mutze cap (model issued since summer 1943 and read #7),and I wonder if he was indeed sniper, as he used almost no sniper tricks except for dummy, despite Zaytsev and his fellows used almost everything – rifle camo, dummies, periscopes, etc. And he must travel with a laundry in his pocket – his parka is always clean.
7. Temperature during fall-winter 1942-1943 was well below -30. It was a VERY early and cold winter. So a boy wearing shorts (shorts! shorts again!) must be a product of some devilish NKVD studies on growing frost-resistant Soviet children. And German sniper’s ears must be fitted with some Aryan magic heating device, as he wears his mutze all the time.
8. On a banquet in 1942 Soviet hymn is played. Eeery – this tune became a hymn after fall 1943, but words are even better – they are 1977 edition.
9. Soviet attack starts with a whistle – nonsense. Soviet attacks started silently and then they grew into some mix of “Ura!” and genuine Russian “mat” 🙂
10. Bloodthirsty comissars shooting their own soldiers using machineguns – nonsense. An officer – who’s duty was to lead his soldiers (that is why Stalingrad was named “a grave for junior lieutenants”) – could and was obliged to shoot cowards or deserters with his pistol, but no back-hitting lead rains from comissars. That could lead them to court-martial and “blam!”.
11. Oh yes, on comissars – they were officially disbanded on October 9 1942. So I guess they are a bit off-time, especiallty wearing uniforms obsolete since 1936 and screaming into voice-pipes (German sniper, where are you?).
12. Danilov and Zaitsev (by the way, nobody uses full names like Vasily, he is Vasya for his friends and Zaytsev for his superiors, e.g. Mathew – Matt) are celebrating their 15 minutes of fame. Well, no comments. I’m afraid there’s no other concept farther from fighting Russian’s mind than “15 minutes of fame”.
13. Danilov (he can not be a comissar, you remember?) writes a letter where he accuses Zaitsev of having an affair with a Jewish girl. I always knew Danilov was Nazi and wanted to commit suicide! Anti-Semitism or any other nationalist stuff was punishable by Soviet laws. During war at front lines Soviet law had a very nasty habit of being 7.62 in diameter. Having an affair with a Jewish girl could not be a crime. That could be a crime if that affair made harm to troops’ morale, was an actual rape or caused a spread of venereal disease.
12. On with affairs – majority of women fighting at frontlines, especially female snipers (women were NOT allowed among frontline troops, only as specialists) lived a very strict and sober life apart from men. Any attempt or insult, or rumor was often punished by the same 7.62 law, potential rapists by women themselves. Any initiative – if any – could came only from them. So, I’m afraid no sex in -30 in common bedplace, alas. Even savage Russians prefer warmer and more intimate conditions.
13. Czech-made T-34-85 looks very genuine in Stalingrad ruins, trust me.
14. Nikita Khrustchev drinking vodka with Daniliov looks like a Zeus asking some shepherd to scratch his back. It just couldn’t be this way – generals don’t drink with second lieutenants 🙂
15. Nikita Khrustchev was a bit younger during Battle of Stalingrad times.
That’s just things I remember. There are more…
duskwight
duskwight,
Wow! And that is one of my favorite movies. I always wondered about the Khrustchev bit. It seemed to me like they got his personality right but the fraternizing thing went too far.
As for the rest of it, I can’t name a movie that doesn’t have gross errors. I guess “Saving Private Ryan” came close for a war movie, but even then they made mistakes.
B.B.
B.B.
This is a bit more than gross error. It’s not about this very film, it’s about general misconception and stupidity. Russians and Soviet army are portrayed like a horde of savages, driven into battle by crazy comissars, using “bury’em with our corpses” tactics.
Following Annaud’s logic “Saving private Ryan” or “Band of Brothers” was to be filmed about a bunch of cowboys, voting on their commander’s orders, munching hamburgers and dancing to “Yankee Doodle” 🙂
duskwight
matt61,
Yes, but, statistically, is he useless?
Great to see the PA blog back up! Other forums and blogs never quite fill the void. I found myself trying to compensate for missing The GAT part 3 on Thursday by spending more time elsewhere, and it felt empty. Not to mention how pathetic it seemed to be checking the PA blog every 10 minutes for the first few hours after the server crash to see if things were back to normal. At times like these, it becomes more difficult to rationalize away my addiction. 🙂
B.B.,
I don’t know why I thought the BSA Scorpion was regulated, but looking back, I don’t see anything that says it is. Can you speculate as to whether or not a regulator would be a good option for more consistent shots/fill in the Scorpion? I imagine the hammer spring would need to be lightened as well – it’s got to be pretty stout if the curve peaks at such high pressures.
– Orin
Orin,
This would be a difficult rifle to regulate because the valve isn’t balanced for lower pressure. The valve would have to be rebuilt. I’d say regulation would be a waste of time on this one.
B.B.
B.B.,
Thanks.
– Orin
I am impressed with the group sizes of this Scorpion! I would not give another rifle a second look if it didn’t group at least as good as this one, and I’m talking at 10m. This one, grouping like this at 50yds, is really impressive. Definitely very useful as a hunter.
-Chuck
Orin,
You both embarrased me and made me laugh at the same time because I did the very same thing, except all weekend long. And I frantically sent out emails looking for answers. Deep down I knew the answer but I just could not accept the fact that it wouldn’t be available until Monday at the earliest. Having been on technical support myself, on my old job, I knew I wasn’t going to be the one to go in on Easter to fix it.
-Chuck
Chuck,
Yes, I also was checking all the time, but knew the blog was down cause no comments were coming in my e-mail account. However, present comments to the old posts are becoming much fewer. I’ve been wondering why and if anyone has an answer I love to hear it.
Bruce
Mr B,
I have an answer – I think it’s because we have been directing everyone to the new blog and telling them not to worry about being off topic so there may not be many reading the old anymore except for the infrequent, sporadic Google search hits by newbies.
Also, I did get SL’s question and I will post the answer tomorrow. I have to get the film developed first.
-Chuck
Edith,
On the beta site, when I click on Crosman rifles, the Challenger with sights doesn’t show up. It still shows up on the old site. Which is interesting as the un-sighted version is out of stock and the sighted one is still in stock.
Chuck,
Great find! I emailed your findings and another issue that I found related to this.
The comments from this blog will keep the IT team hopping!
Thanks,
Edith