Chronograph tips

by B.B. Pelletier

I’ve probably said these things before, but they’re fundamental and bear repeating. With more of you starting to use chronographs, you need to be aware of some of the basic operational tips for the equipment.

Before we go any farther, know that I’m limiting my remarks to the Shooting Chrony-type of chronograph that uses an incandescent or natural light (sunlight) source. There are various chronographs that use infrared light sources and these notes do not necessarily apply.

Lighting outdoors
Outdoors you want an even source of light, with an overcast sky being the best. The worst is direct sunlight falling on the skyscreens. That condition is what the diffusers are for, so use them. A day where clouds are being blown all around is a tough day to chronograph outdoors.

Lighting indoors
Fluorescent lighting does not work with a chronograph. A fluorescent light flickers at speeds imperceptible to the human eye (most of the time), but the sensitive skyscreen will be set off. When that happens, you’ll get spurious readings, errors and half-readings. That can be a big problem, now that many households are converting from incandescent lighting to fluorescent. You may have to kill all the lights in the room to get the chronograph to work.

Mercury vapor lights found in warehouses and workshops can also be problematic. Whenever your chronograph starts firing on its own, you probably have a lighting problem.

Direct light sources are another way around indoor lighting problems. There are commercial skyscreen lights you can buy or you can make a light bar of your own with parts bought at a hardware store. A much simpler way, if you shoot in a room that has a ceiling painted a solid light color, is to reflect a bright light off the ceiling and let the skyscreens look at that light. This is how I do it in my office, which has a 10-foot ceiling. I use a photo light, but you can use a 500-watt halogen work light shined upward.

Chronograph tips
Here’s the big one. Keep the muzzle of your gun at least a foot back from the starting skyscreen. This is especially true when testing the powerful super magnums, such as the new Benjamin Trail NP XL1100 I tested for you on Monday. In fact, it was while testing that rifle that the idea for this report was born. I held the muzzle of the gun too close to the start screen a couple times and got several shots that measured 300 f.p.s. slower than they should have. That’s not the gun acting up. That’s the chronograph operator’s fault.

If we had a super-fast video camera filming the muzzle of a spring gun, you would be able to see a ball of pressurized air that comes out of the gun ahead of the pellet. If the pellet travels at 900 f.p.s., this ball of air goes about 1100 f.p.s. for a couple inches. If the muzzle is held too close, the skyscreen senses the ball of compressed air and starts the clock. Once the clock has been started the pellet has no effect on it anymore. Of course, the pellet passing over the stop screen stops the clock and now you have a longer interval on the clock than the pellet really should have registered. More time equals a slower pellet transit time, hence the readings are slower than they should have been. Just by backing the muzzle up 12 inches from the start screen, you take care of 100 percent of this problem with all spring guns. Maybe with some powerful pneumatics like the Condor you should back up 18 inches. And certainly with a big bore I would back up 4-5 feet. The pressurized air will still be seen by the skyscreen, but by backing up you allow the pellet/bullet to trip the sensor first.

Tip #2–stay level
Both skyscreens look in the same direction. If the chronograph is flat on a table, both skyscreens should look directly upward so they are set up to calculate the passage of a pellet that flies perpendicular to their line of sight.

If you angle a shot through the line of the skyscreens, the time it takes to trip them will be longer that it would have been if they went through at a perfect perpendicular angle. That’s because an angled line through two planes is always longer than one that passes through perpendicular.


The slanted line through the top chronograph is a longer path, resulting is lower indicated velocities. The bottom chronograph shows how the rifle should be fired.

Maybe the explanation is difficult to follow, but look at the drawings. I can slow down any gun by slanting the line of the pellet through the skyscreens. Try it yourself and you’ll see what I mean.

Tip #3–clean those skyscreens
If your chrono has any age to it, your skyscreen shields are dirty. Those are the clear plastic “lenses” that cover and protect the real sensors. Use a Q-tip to clean them, and your numbers will be easier to obtain.

Tip #4–watch your angle
As well as watching the up/down angle through the screens, you also need to be careful of the sideways angle. You will get an “Error 2″ message when you miss screen two, which is the most common error you’ll see, because the start screen (screen 1) is closer to the gun and harder to miss.

Well, those are some things to think about when you use your chronograph next time. They’re wonderful instruments that respond best if a little care is used during their operation.

85 thoughts on “Chronograph tips

  1. Morning B.B.,

    Thanks for the chronny tips. I don't want to think about how long it would have taken me to figure out that the sensor protector "lenses" were dirty.

    Have a wonderful day!

    Mr B.


  2. Side note: I believe not all flourescents are equal in this respect. I've used compact flourescents (CF) bulbs as a light source without any problems.


  3. Hello,
    totally off topic but I wanted to know if the remake of part four on your wonderful bronco was coming soon ?
    I was planning on buying one since all the reviews on it are so wonderful and I wanted to scope it so I would like part four before clicking the "add to cart" button.
    Speaking of scope I would like a 3-9X scope under 100$, I was thinking of a leapers or a center point am I correct with this ? Any suggestions would be greatly appreciated.

    Thank you

    J-F

    wv : "tests" the best ones are found right here !


  4. B.B.
    For outdoor shooting, I find that going out fairly early or late in the day works best on a sunny day.
    I set up the chrono in the shadow of a building or very thick tree so that the sensors can look at the sky, but there will not be direct sunlight on the sensors or reflecting off the pellets.

    One gremlin that I saw that took me a few minutes to figure out….
    I was shooting my bow over the chrono as I tuned it. There were a lot of times that the chrono registered an error just as I was ready to shoot. WTF????
    I got to watching, and noticed that there were a lot of bugs in the air. Every time one flew over the chrono it errored.

    twotalon


  5. B.B.
    Something I saw once…
    One of our club members (muzzle loading) borrowed a chrono from someone and brought it to the range. It was mounted on a heavy steel frame with a heavy angled steel deflector plate in front of the display.
    As the story goes…
    The first time the chrono was used, the guy's(owners) buddy was shooting a 30-30 and aimed right at the deflector plate. Left a pretty good pock mark but saved the chrono. (right in the center too)


  6. I wanted to test a B4-2 air rifle at a longer range to see how much the pellet slowed down.

    Guess what?

    I shouldn't have been surprised that the Shooting Chrony people 1) sold the LCD display as a replacement part, and 2) they had them in stock for immediate shipment.


  7. J-F,

    The scoped Bronco is coming soon, but why wait for that? We know for sure that the rifle is very accurate. The scope will only improve that.

    After I scope it, I'll mount a peep sight on it for another report.

    B.B.


  8. twotalon,

    Your .30-30 story was done with a scoped rifle, no? I should have included that, as a scoped rifle at close range ALWAYS shoots low!

    Reminds me of a similar mishap on an M203 grenade launcher range in Germany. Used the rifle sights and hit the wooden berm 3 feet in front of his position!

    B.B.




  9. Concerning fluorescent light, there is a quick and easy test to determine if your light source is 'flickering': Keeping your eyes straight the whole time, rotate your head smoothly and quickly about 90 degrees. Don't move your eyes while doing this! You will readily perceive the cycling rate of the light source, if it is not too high. Standard long tube type fluorescent bulbs cycle on and off at 60 Hz (60 cycles per second) the same as the alternating current (AC) that feeds them. Normally, if you are not moving quickly, this is fast enough that the light seems constant. You have all seen film or videos of computer screens that seem to be flickering badly. That is because the refresh rate of the computer screen and the external lighting are either in sync with each other, or almost so, and videotaping a computer screen really brings this out. If screen flicker in a fluorescent-lighted environment drives you nuts, simply change the refresh rate of your display to 80 or 85 Hz and your problem is gone.

    Some of the new CF bulbs have a cycling period that is much faster, and you will only see the 'on-off-on' effect if you really jerk your head around very fast, but be careful- don't get a crick in your neck! Incandescent and halogen bulbs are "constant on" and so are much better for chronies, and less tiring on your eyes in the long run. Although you may not consciously perceive it, your brain does perceive the cycling and is constantly adjusting the image it is processing through your eyes. This is hard work and will tire you much faster than reading or working by natural or incandescent light.

    Okay, enough extraneous blabbing.

    -AlanL


  10. B.B.
    I use an older (15yr+) Pro Chrono that is very sensitive and consistent. It never has given any bad readings through any fault of it's own.
    I like to set up the bench with bags and with the chrono on a tripod. I adjust the tripod until the bore line is right down the top center of the chrono. Then I drop the tripod by 3-4". Works fine.

    twotalon


  11. Funny that you would post about shooting over a Chrony. Recently did so with my newly converted 1377 Carbine, shot with the muzzle only a foot away from the Chronograph, and people asked if I would do it 3 feet away instead "to have better comparing figures".


  12. E in V
    Sounds like they want to compare to their own figures.

    First of all, a couple feet different is not going to make a rat's butt difference in velocity.
    Secondly, the differences in accuracy of different chronographs can be way different….giving much larger differences in velocity than a couple feet would.

    twotalon



  13. B.B.

    truth is I never bought a real scope the only real scope I own is the centerpoint one the came with my summit rifle so since this will be my first I don't want to mess it up and I can't afford to mess it up, I live in Canada where thanks to our great laws the bronco is considered a firearm so I'll be ordering it from PA while in the US and sneaking it back here but if something goes wrong I'll be toasted because I won't be able to return it.

    J-F




  14. You also forgot to remind shooters that they need to allow for the difference in the line-of-sight through the scope vs the line-of-flight of the projectile. (especially with a high mounted scope)
    I have heard many stories of people shooting their chronies due to them sighting through the crony and forgetting that the barrel is lower than their point of view at that close range.
    Maybe a good plastic shield at an angle in front of the chrony would be a good idea. Too easy to forget when busy shooting.


  15. J-F,

    You've made a good chopice in rifles. I'm going to suggest not over scoping your gun. By that I mean, it's a small light weight rifle that can quickly become top heavy and loose it's excellent handling by having a too big and heavy scope mounted on it. Check out PA's scopes and look at this one Item#: SCP-392AOMDTS[PY-A-866.

    Mr B.



  16. Edith,

    I've got B.B.'s post appearing twice when I open up Blog from PSA's website. Is it my PC seeing double or is it blogger wqorking his magic?

    Mr B.



  17. Revwarnut,

    Y&es I forgot to include that warning. My own Crony has a dent in the case and my Oehler skyscreens (always the number two, or in this case the number three screen) is shot up.

    B.B.






  18. Mr. B

    Thank you very much it's exactly what I'm looking for, I'm chatting with a very helpful PA rep right now about the choice of rings for it, it'll be ordered by the end of the day.

    Thanks again

    J-F




  19. Bub, yes, the QB78 is still avalable. If you just google 'QB-78 air rifle' you'll come up with some vendors. Can't mention them here… bad form advertising another store on pyramyd's site!


  20. AlanL,

    Yes, the longer scope has an illuminated reticle, which is of dubious value to most shooters.

    The Mini is limited as to where it can be mounted, because the tube length is so short. I like minis some times, but their limited positioning can be a pain. I think on the Bronco it would work, but remember to use two-piece rings.

    B.B.

    B.B.


  21. Rikib,

    I think it's good your thinking of waiting a few weeks on your next air gun purchase.

    I've tried 3 of the Avenger 1100s. Two of the mendoza 2800 and 600s (mendoza 600 and Avenger 1100 is about the same gun). These are very good springers for the money… but, I don't like the 2000 – 2800 series with the 7 shot mag. There is too much air loss at the double breech seals.

    Another great spring gun for the money is the midsize RWS 92 at 650fps (8.4gr pellet) or the full size RWS94 at 900fps 10gr pellet. Both have good triggers, but the 94 has the best trigger of all I mentioned here.
    The RWS 94 and 92 are discontinued by RWS and so you have to find them used on the Yellow Classified: (skip the RWS93, the trigger is terrible!)

    http://www.network54.com/Forum/79574/

    I still have one extra RWS 92 I might be talked into selling, but try to find your own first. You should only have to pay $100 or so for a decent used one with open sights. or.. $150-$200 for a good used RWS 94.. The 92 is much easier to shoot accurately, with a lot less recoil.

    CO2 can get expensive with all the little cartridges.. but at least you live in a moderate climate, so the cold temp is not as much of a factor. As the temp gets above 70, your velocity and shots per cartridge will increase a little.

    Welcome back!.. I'm glad you figured out our system, this is a great bunch of folks here.

    It won't take long to get totally hooked and your budget will change drastically in the near future…

    .. but like Volvo said, they can turn over real easy on the yellow.. so think of it as a savings account of sorts.. Just ask Frank B. :-) (that's a smile)

    Wacky Wayne, Match Director,
    Ashland Air Rifle Range


  22. I posted this previously (Jan 10) but this is a good place to re-post it.

    A long while back I think I said I'd report how my new chrony worked after getting a lot of good advice from you all on how to set it up. What I ended up doing, and has worked flawlessly so far, is to buy one of those double halogen light work lamps from Harbor Freight for work in my garage. The lamp was very inexpensive (~$20), sturdy, and has an adjustable tripod stand and at least a 6 foot pole that can be telescoped to any height between 2 feet and 6.

    I thought I'd try it out on my chrony to see if it would work. I extend it to the highest limit and shine it directly down on the light diffusers. The two lamps are conveniently spaced exactly the same distance as the light diffusers and the tripod legs allow me to slide them in under the chrony tripod legs and get the lamps directly over the center of the diffusers. I have mounted the chrony on a standard camera tripod. The chrony has a standard camera tripod hole in the bottom for that reason I assume.

    The halogen bulbs are 300 watts each. (in my previous post I said 150w but closer inspection revealed 300w) I don't remember the original wattage (max rating is 500) but after breaking one in the garage while working on my car, I replaced them with 300's.

    The resulting setup is easy to establish and the light shining DOWN through the diffusers instead of up and then reflecting down is much more pleasing to me and casts a very good direct pellet shadow over the sensors. Since I have to turn off all the flourescent lights in the basement the halogen light makes it easy for me to get around, too.
    -Chuck



  23. AlanL,

    In my humble opinion.. here is the best scope for the money… period.

    http://www.pyramydair.com/s/a/Leapers_Golden_Image_3_9x32AO_Rifle_Scope_Mil_Dot_Reticle_1_Tube/866

    It's hard to find on the PA site.

    It focuses down to 6 yards! wide field of view, very durable, good adjustments, small, light weight, and fits the Bronco perfect! and very, very affordable!

    The next size larger 3-9x40AO is great too, but you need high mounts and the higher your scope, the more potential problems you have.. keep your scopes as low to the barrel as possible.

    I don't like the "Bug Buster" the cross hairs are too thick for me, and like B.B. says your mounting options are very limited.

    Wacky Wayne, Match Director,
    Ashland Air Rifle Range


  24. B.B.

    My main concern with the chronograph is blowing it away by accident. But it seems to be indispensable for both tuning pcps and for precision reloading.

    Bub, I might add about the QB78 that Mike Melick does terrific tunes on them. Have a look at his site at Flying Dragon Air Rifles.

    AlanL, that's a new one about wanting to experience springer recoil when you have an RWS 54. A cheap way to do that is to get an IZH 61 which is probably the price of renting an RWS 48 if such a thing were possible. The IZH 61 will test your understanding of the artillery hold and reward you when you've got it.

    rikib, welcome. You are rich indeed with your set-up with the railroad tracks and lacking only a nice supply of dead wood to play with….

    andreas, I thought you were still in the Greek army.

    All, thanks for the advice on cases. I've heard of the Pelican as an expensive option, not StarLite. Good leads. Considering that I routinely transport almost $3000 at one time, it doesn't make sense to skimp.

    On the subject of the history of guns, my imagination was jogged not only by yesterday's post but by a listing at the James River Armory (for which I thank Joe Springfield for his reference, great site). They've got a restored Russian capture Mauser 98k with a shiny new bore. Wow. If one could somehow follow the life of a gun as it changes hands between owners and across national boundaries, it would be something to see.

    Matt61


  25. B.B.,
    The Shooting Chrony folks have a reduced cost trade in program for your old Chrony, even your "shot up" chrony, not that I ever shot mine up, LOL.

    My chrony is set up uderneath a ceiling-hung gas heater in my garage, and when the fan motor cuts off it will sometimes throw a fake reading into the chrony. Back EMF, I guess.

    I've also used a piece of white translucent corrogated plastic roofing as a sky shield to even out the light to the chrony.

    Just a couple of thoughts,
    Lloyd


  26. J-F,

    Thank you. Please keep in contact with us and let us know how you're progressing with your gun and scope.

    CJr,

    I'll have to go to Harbor Freight one day this week and purchase one of those lights you told us about.

    Wayne,

    It's good to hear from you and nice to see that we agree on that Leapers scope. Gotta ask if you ever took a look at Freedom Arms hand guns and if so what do you think of them?

    Mr B.



  27. Mr. B.

    Yes, I did look at the Freedom Arms hand guns.. Thanks for the idea…

    Wow, what quality… They are something to look forward too as my season progresses:-)

    Wacky Wayne


  28. Alright, I've been putting it off for quite a while, but I guess I'll have to add a chronograph to my list. It might be a few months before I order it. Although, do I really need it? Oh, well, we'll see.


  29. blowgunner62,

    A suggestion for you to consider is to also buy a printer or at least a chronograph that is compatible with a printer. It gets old writing down shot strings, etc.

    Mr B.

    WV = tublersi, another disease of wild rabbits?


  30. Thanks to everyone who helped me pick a scope for my bronco including the wonderful PA rep, they're really nice and are a real plus for the business.

    J-F


  31. BB,
    I have had my new Remington npss for a couple weeks now and after about 500 shots i decided it was time to read the owners manual. Well when i read the section for maintaining the gun it said to put a drop of oil down the compression chamber every few hundred shots. This seems like a lot of oiling for a spring piston rifle, do gas piston rifles require more lubrication? -Rich



  32. The new LED light for the Chrony is awesome! The lights are built into the screens and they come with the longer rods in one piece instead of two (the two always seemed to slide apart). What's weird is that the light is a very dark red and not bright at all. I guess they figured out that it gives the best shadows for the sensors. Do yourself a favor and get these! Never get an error 1 or error 2 or error 9 or error "I'm going to freak out because my string just got messed up" again!


  33. blowgunner62,
    I second the motion on the printer. It is such a valuable addition to the chrony itself. After a ten shot string you'll want to print out the shot string and the summary info you're always reading about in BB's tests. Also, I always save the chrony "tapes" for future reference. If I have a gun that seems to be losing its punch I can look back and see what it used to do. With air I can reference past psi pressures I've recorded for the shot strings and with CO2 I can reference the number of shots I have gotten out of a bottle. I roll the tapes up into a cylinder and store them on end in a box. You can fit a lot in that way and they're very easy to find and take out. Plus it's another way for me to feed my analosityness.
    -Chuck




  34. j.
    I had to try that link three times before I could get to work. For some reason it acted like it was an invalid string, but on the third try it worked. Go figure! don't you just hate computers sometimes?
    -Chuck




  35. J.
    For kicks I waited a couple minutes and tried it again and it worked on the first try. Sometimes it helps to exit completely out of your browser then start it up again, sometimes that helps.
    -Chuck


  36. Thanks guys. That's weird… that its not coming up. Maybe its a quirk with Internet Explorer 8 or something. I'll try clearing everything and trying it again.

    J.




  37. BB, Edith…

    I tried it in two different browsers (IE8 and Opera) on two different computers (one running XP and one running Win2K). I cleared the cache on both browsers. Nada. I'm not sure what's going on at this point. Especially since this isn't the first time I have tried to access that article and had this happen. Maybe its an issue with my ISP or something. Though if that was the case I have to wonder why I can access the other Pyramid Air articles…

    Its not critically important or anything since I was able to use other sources to answer the question about airgun power levels (someone tossed out a comment that Gamo Hunter Extreme was the most powerful airgun and I was going to use that article to rebut that claim since you had chroni numbers for the Hunter Extreme in it). I just figured I'd ask in case it was effecting other people too.

    J.


  38. Although, I've had no trouble with my disco and pump, I do sometimes see people wondering what to do if they encounter a problem with their Benjamin Hand Pump. I couldn't find the info listed here through the search, so I seached the yellow forum where I have seen this info before. Actually, this info from several reputable bloggers.

    Benjamin Hand Pump Repair:

    Sun Optics USA is working with Crosman to repair and rebuild their pumps. If your pump is out of warranty they will rebuild and test for you for a cost of $25.00 which includes all parts labor and shipping back to you. If it is in warranty contact Crosman first for verification and then send to us. If in warranty there will be no charge to you.

    Sun Optics USA
    2901 Suffolk Dr
    Suite 130
    Fort Worth, TX 76133

    817-350-4957

    Popular Contact Representative: Duane Sorensen

    Price listed for repair is most likely for CONUSA Shipping and subject to change.

    -AJ



  39. Edith,

    Yep. I can get to that article without any problems. Ditto on the one about the artillery hold ( http://www.pyramydair.com/artillery-hold-video-article.shtml ) and the one about the Little Rock Airgun Show ( http://www.pyramydair.com/2009-little-rock-airgun-show.shtml ). For some reason its just that article. That's why I thought there might be something going on with that article. (Maybe the Gamo marketing team hexed it because BB didn't lovingly confirm their claims about how fast the Hunter Extreme shot? lol.)

    J.


  40. Rikib,

    I posted on yesterdays blog, but here are the basics of replacing the 2240 barrel.

    -Remove the barrel band
    -Cock the gun and with the bolt in the rearward position, remove the little breech screw (requires 0.05" hex wrench) that was under the bolt.
    -Gently lift the front of the breech up (still held by rear screw) and slide the barrel out. Lifting the breech is necessary because a metal sleeve fits into a hole on the bottom of the barrel.
    -While holding the breech up, slide the new barrel in and lower the breech back onto the main tube. The hole on the bottom of the barrel must slip onto the metal sleeve mentioned before.
    -Install the breech screw.
    -Install the barrel band.
    —done—

    Here is a link to a 1377 disassembly, the relevant parts are the breech instructions.

    http://www.network54.com/Realm/CFTech/JTP1377.htm

    Its been awhile since I've done this so hopefully I didn't forget something. :)

    Of course while your at it, you might want to go ahead and replace the breech with a steel breech :).

    AR


  41. Rikib,

    You might need to loosen the rear breech screw (on top of the rear site) too.

    Now I need to go patch up our backyard fence from the oak tree that crashed down on it this afternoon (thankfully it didn't hit the house)!




  42. A.R. – An oak tree …wow…we used to cut trees and cut them into logs. A good old oak tree could provide a lot of wood for the fireplace. Glad to hear everyone is OK.


  43. I maybe wrong but I think that about a week or so ago someone mentioned putting pellets into a tumbler to help clean them off before using them. Was there a post about that or am I just imagining it. On another note are Crosman premier pellets of a higher quality than Gamo magnums? The reason I ask is that I purchased the Gamo pellets with my 2240. I normally press about 20-30 pellets at a time (how many I plan to shoot) into 1/8" foam board before using to check for any noticeable problems and it seems that the tail ends are not very consistent in shape (conical). What do you all feel is the best brand for consistent quality?


  44. Rikib, Gamo pellets aren't bad, but they really aren't that good. It's a fair general-use pellet. Sometimes you'll find a gun that does particularly well with them, but I don't think it can be said that they are among the best.

    Crosman Premiers (in the brown boxes, that is) – on the other hand – ARE among the best. The hollow-point Premiers in the metal tins (along with their Benjamin Discovery counterparts) aren't as consistent, but are generally very good. Except when Crosman gets a bad production run. In my personal experience the Premier pointed pellets are terrible, and the Premier wadcutters are no better than the bulk-boxed (and cheaper) Copperhead wadcutters. Oddly enough, the few times I've tried the CHEAP Copperhead pointed pellets they've done very well.


  45. does "dry firing" a CO2 pistol harm it in anyway. I was wondering because I always do this pointed at the ground when I'm finished for the day (somehow it makes me feel the pistol is safer). Maybe it is just caution from using "real" guns and wanting to be certain the chamber is clear. So does the "dry fire" harm the CO2 pistol?


  46. B.B.

    I have another question about the Crosman 2260. I would like to do some hunting, but my main use would probably be plinking. Will the 2260 chew up some old tin cans, but still have some stopping power for game? Also is there a way to get shots decently that are decently powered when it is cold even at the expense of the number of shots?

    Thanks once again!!!


  47. So Vince, you feel that the Crosman Premier .22 Hollowpoint is a pretty good pellet in general? I know you said you liked the brown boxed Premiers better, but I'm just a casual backyard shooter at tin cans an paper targets. And wow there is a big price difference between the two. So would the hollowpoint do for my needs? I'm shooting a 2240 (unmodified for the moment).


  48. ajvenom,

    Yep, our primary heat is a wood stove so we should have a good portion of next winter's wood! Another fortunate thing is that our labs didn't discover the break in the fence until I was patching it (in fact they snoozed through the fall). With some help from my son, they didn't even notice while I was cutting the tree off the fence with my chainsaw. By the time they noticed, it was too late :)

    I enjoy cutting wood. A group of us cut wood spring and fall to supply wood in our community for those who can't afford it and aren't able to do it themselves.

    AR


  49. Rikib,

    Dry firing the 2240 occasionally shouldn't be a problem. The only real problem I would see is if dry firing causes the valve stem to strike the opposite end of the valve body since there isn't as much back pressure. I don't know if this will happen or not.

    Here is an article BB wrote about pneumatic valves (a lot of airguns use a poppet type valve).
    http://www.pyramydair.com/blog/2006/10/diagram-of-pneumatic-valve.html

    Here is a picture of the BOSS valve cut open (the same as a 2240 valve except it has a bigger volume).
    http://www.bryanandac.com/images/Boss7.jpg

    AR


  50. I'm no expert but tumbling pellets seems like a way to damage their skirts. I'd be leery about doing this. I have noticed metal chips in the tins of some pellets so I know there is a potential problem of some sort. I don't know of any way to eliminate them safely. The air blower technique seems viable but pouring the pellets from one tin to another while blowing seems risky also. I think the safest way would be (if you are really serious about accuracy) is to weigh each pellet individually and sort them in that order. Now this may sound silly but with today's digital scales this is easy and accurate albeit time consuming. However, it's not something that can't be helped with a good TV program.
    -Chuck


  51. The Crosman 2260 has roughly 12 foot-pounds of muzzle energy. On a warm day (70 degrees F.) it will dent steel cans and completely penetrate aluminum cans at 30 feet.

    It is powerful enough to take small (cottontail rabbit-sized) critters, providing you are a good enough shot to hit the brain reliably. So only shoot from a distance at which all your shots are on an American Quarter.

    Used domed pellets for the best accuracy. Crosman premiers in the cardboard box are the best for this rifle.

    B.B.


  52. Rikib,

    No, Crosman Premier hollowpoints are not as accurate as the boxed Premiers. That's why the boxed Premiers cost so much.

    However, Premier hollowpoints are an acceptable cheap pellet.

    B.B.



  53. Anonymous (not getting today's blog),

    Maybe so, try learing your cache and see if that helps. Unfortunatly that is the end of my tec knowledge.

    If that doesn't work, let me know and I'll post your question on the current blog.

    Mr B.


  54. LED lightkit guy…
    I've heard and read nothing but good things about the new LED light kit that is now offered by Shooting Crony so I ordered one. Should be here tomorrow. Expensive, but to me worth it, because I'm tired of having to use my clamp lamps and its just a big PITA whenever I want to shoot indoors and measure velocity. Looking forward to using it.


  55. Rikib, I suspect that the Premier HP in .22 is the best plinking pellet for the money. Once in a while I run across a gun that doesn't like them, but that's the oddball.


  56. I put this question in before, but I guess it went missing 8-) When using a chrony at a distance, my understanding is that the pllet is going to be on the way down, so how would one measure the speed of a pellet at distance if it was going down at an angle? Maybe you just shouldn't?

    Michael in Georgia


  57. Zevtov, that's a good question and you are correct. Depending on the distance you've placed your Chronometer from the muzzle, the pellet will either be rising or falling. For instance, if your chronometer is placed say 1' from the muzzle, the pellet could be level or rising (if you're shooting with a scope) or even falling if you try to hold the barrel level. What is the error?

    Since the Chrony A that I have has, I believe, a distance of 1' between the 1st and second electric eyes, I have to believe the error will be insignificant. How do we measure something like that or calculate it? Questions like these in my calculus classes in college drove me nuts. Now I can say, I don't know.

    Sorry.

    Fred PRoNJ


  58. Zevtov,

    that's not exactly true. Without using calculus but High School physics, we know the pellet is dropping 32' per sec squared (gravity). We will know the time it takes the pellet to pass from the first to second screen (working backwards from the readout in feet per sec) the chrony gives us, we can then calculate the distance dropped. That distance will be the hypotenuse of a triangle which is longer than the straight line distance. This isn't exactly the case as the pellet is taking an arc or curve, not a straight line drop but it's good enough for our needs. We're almost there. So, the pellet has travelled a longer distance but the Chrony "thinks" it has travelled a shorter distance (straight line vs. the hypotenuse of the triangle) and therefore the Chrony will give a SLOWER reading – based on a shorter distance traveled in the alloted time. At 40 yards, that hypotenuse will be longer as the pellet slows and therefore drops further since there is more time for gravity to act on it.

    Do you want me to continue? :)

    Fred PRoNJ



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