Air Arms Alfa Competition pistol – Part 2

by B.B. Pelletier

Part 1

Today, I’ll look at the Alfa Competition pistol from Air Arms for a second time. You may remember me telling you that this would be a longer report because there are complexities with target guns that you don’t normally encounter with a sporting gun. The biggest of these is finding the right pellet for the gun. That can take a very long time, so I’ll tell you how I do it, but I’m not going to actually find the very best pellet for this particular pistol, because I haven’t got enough time. That will be in another report, though.

Let’s look at the power curve. I want to know if this pistol has enough air for a men’s match, which is 60 shots, plus sighters. I’d normally skip this step because all the 10-meter PCPs pistols I’ve tested are regulated and have a more or less standard-sized air reservoir under the barrel. This one does not. It stores the air inside a small tank in the grip, so I added this important step just so we’d all know if the gun was useful for match shooting.

Filling the gun
Since this is an air pistol, I’ll fill it with a hand pump. It takes so little air that i think a scuba tank is unnecessary. The number of pump strokes that are harder (i.e., those above 2,500 psi for me) is so small that it’s easy enough to just grin and bear it.

The instructions say to fill to 200 bar. Since 3,000 psi is only 6 bar more, I filled to that pressure the first time, just to get a good look at both ends of the power curve. As it turned out, that was unnecessary, because this gun does not like to be filled even to 200 bar. I’ll look at the velocity data and pick a better stopping point for the second fill. I’ll talk you through the logic of how this is done, including some shortcuts.

You may remember that I dislike the Air Arms fill adapter. It works fine, but the gun always ends up in a strange position because of how the adapter fits, so it’s not my preference. It does screw onto a standard 1/8″ BSPP thread, though, and that’s a known standard for PCP gun charging equipment.


This is the fill coupling on the butt of the pistol. The two o-rings needed silicone grease before the adapter would slide on.


The Air Arms fill adapter slips over the two o-rings and locks up with the gun through a key on the fill coupling.

Checking the power curve
Those who are thinking about getting into precharged airguns, this procedure is an important one. It requires a chronograph, which I feel is an essential part of PCP equipment. What you do is chronograph all the shots, using the same type of pellet.

A regulated gun will start at a certain velocity and remain close to that velocity until the pressure in the reservoir has dropped below the minimum pressure the reg can handle. After that, the velocity declines.

An unregulated gun will usually start slow and then climb if the gun is slightly overfilled. That’s a good thing, because after you have the velocities recorded for all the shots you will test, a velocity curve will be revealed in the numbers.

The Alfa Competition Pistol is definitely unregulated, and the velocity curve shows it. Shot No. 1 with 7-grain RWS Basics was 395 f.p.s. Shot No. 2 was 411 f.p.s. and the gun never again dipped into the 300s. Shot No. 6 went over 420 f.p.s. But it took until shot No. 22 to go over 430 f.p.s.

Shot No. 34 went faster than 440 f.p.s., so the curve was still on the upward slope. Can you see clearly that this pistol exhibits the classic signs of being unregulated? And can you also see why this test was necessary? Until I know the performance curve, I cannot know how many good shots there are, nor can I know what the starting fill pressure really should be. This is why a chronograph can be so important when testing a new PCP. They don’t all perform like it says in the book!

Shot No. 43 inched above 450 f.p.s  for the first time, but the velocity was still climbing. It didn’t get back that high again until shot No. 50, but after that it didn’t want to come back down, either.

Shot No. 58 topped 460 f.p.s. for the first time. And shot No. 74 went 474 f.p.s. At this point, I knew the pistol was not going to exhibit an inverted “bathtub curve” with an upward slope followed by a relatively large flat spot at which all the velocities are very consistent and then a similar downward slope. From my experience, this gun looked like it was going to keep rising and then flatten at the end for a short string, followed by a precipitous drop when it came off the curve.

Shot No. 98 finally topped 480 f.p.s. for the first time, and I expected the velocity to tank fairly soon thereafter. At shot No. 113, the falloff began. Shot No. 112 went 460 f.p.s. and the next shot went 435 f.p.s. Four shots later, we were at 415 f.p.s.–having fallen sharply off the performance curve.

So, what does this tell us? First, that this pistol is unregulated. Second, that no matter where we select the best fill level, we will have to be content with a broad velocity swing over the number of shots we’ve chosen. Target pellets are heavier than Basics, so the swing won’t be as large as 40 f.p.s., but it’ll be close.

At 10 meters, a 40 f.p.s. total velocity variance won’t affect accuracy that much. While I would prefer less of a swing, I can live with it. So, let me look at the performance curve and try to select the best place for competition.

Since I cannot avoid going 480 f.p.s. (the fastest shot went 481 f.p.s., and there were only three like that), I selected the final shot of 460 f.p.s. (shot No. 112) as my end point. If I want 60 shots with five extras for insurance/sighters, that makes my first shot on this string go back to the first shot at 455 f.p.s. There were three shots before that were 450 f.p.s. or faster, so I credit this pistol with a total of 68 good shots. I’ll predict the starting fill in a moment, but I’m not done with the analysis, yet.

Although my first shot is 450 f.p.s., the velocity does dip below that mark in this string. The slowest it goes is 443 f.p.s. The fastest is 481 f.p.s., so the maximum velocity variation in a string of 68 shots is 38 f.p.s. As I mentioned, a heavier pellet will tighten that variation a bit, so expect maybe 32-34 f.p.s. across a 68-shot string. That’s more than I like, but for 10 meters it isn’t going to make much of a difference. So, the question of whether or not the Alfa pistol holds enough air to complete a men’s match has been answered. It does. If you have to shoot the extra 10 shots afterward, you’ll have to refill the pistol.

Determining the starting fill pressure
The way to determine the starting fill pressure for a PCP is to keep decreasing the fill pressure by 100 psi, until the first shot out the muzzle is within the desired power curve. But I have a faster way to get there. Experience tells me that a partially valve-locked valve uses far less air than that same valve uses when it’s shooting within the power curve. Looking at the total shot string I fired, it took me 48 shots to climb to where I wanted to start shooting. That’s very close to half the total shots fired, but from an air usage standpoint, it’s more like one-quarter to one-third the total air used.

I know the start point was 3,000, so I need to connect to the gun and determine the point at which it starts to accept a fill. In other words, the end point. Since I shot four shots after falling off the power curve, I’ll add 100 psi for them and call that number the low end of the fill.

My low turned out to be 700 psi, even with that extra 100 psi added-in (hard to believe, isn’t it?), so I guesstimated the high fill point to be at 2,300 psi. The first shot on a fill at that pressure went 435 f.p.s. and not until 14 shots later did I see 450 f.p.s.–missing the targeted start point by a total of 15 shots. On the next fill, I’ll stop at 2,100 psi and see where that takes me.

My method takes far fewer times than the 100-psi-per-time method. As an airgun tester, I have to use it to cut down on my test times.

I know that there are those among you who want to know absolutely everything that happened in my tests. Herb, for example, will create several algorithms to construct an alternate universe from my data and then attempt to occupy that universe, even as Rocket Jane Hansen seeks to destroy the universe he presently inhabits ;-) You guys and gals are lucky I love you!

So for those who want to know, here are the data, in even columns as they were gathered. They run top to bottom, left column to right column.

I’m sorry those two columns are longer, but when dealing with 116 numbers in sequence and discovering that I screwed up the presentation around number 70, I just punted. The numbers are sequenced exactly as they were recorded and the one that is missing was a shot I lost. It actually went into the wall of my office, where it took my wife about 90 minutes to discover. She wants me to write yet another expose on how stupidents happen (stupidents are “accidents” that should never happen).

So, here’s what I know. This pistol is going to want to shoot slightly heavier target pellets at around 435-460 f.p.s. I don’t want to shoot any slower than that, so the total shot string is going to be about the same as it is now. Therefore, I will not adjust the gun’s power.

That’s it for this time. Next time, I’ll look at some pellets.

28 thoughts on “Air Arms Alfa Competition pistol – Part 2

  1. BB,
    There is just no end to learning is there? I know this info will be useful to me some day, really. Also, there is no end to your teaching. Thank you very much. Also, I’m intrigued by the prospect of an alternate universe where there is this provocative contention between the Professor and the Rocket Scientist. Good material for a sci-fi novel.

    I say your info will be useful to me someday because I am this close to PCP land. Yesterday I took delivery on a Talon SS from PA. Holy Cow! What a gun! I’m shooting the numbers out of my targets! I didn’t know I was such a good shot. I originally ordered the PCP version but the scuba fill clamps were on back order so I switched to CO2 cause I hate waiting. What a sweet gun! Anyway, you’ve taught me some basics for when I get the air hookups.

    BTW, thanks for coming into my living room yesterday ;) It was nice meeting you. The package came with a DVD of no other than Tom Gaylord pumping his heart out filling a Talon, no less. Excellent video! I’m looking forward to the “Tom G’s Aerobic Airgun Workout” video. “Everybody, now – a one, a two, a one, two, three, four – now grapevine left…”


  2. Dr.G..
    Your question from yesterday….
    Shooting 2 pellets at the same time will not damage the barrel, but will give you much less mv and poor accuracy.

    The pellets may fuse together or seperate, but beyond a few yards it would not be reasonable to expect to hit anything you shoot at.

    I remember a long time ago shooting an old benji smoothbore pump with various numbers of BBs at the same time that I got a shotgun effect…..
    The BBs flew all over the place, except for the spot I was aiming. Not very practical.
    Then there is the problem when barn hunting…you get a whole hand full of BBs bouncing right back at you.

    twotalon


  3. B.B.
    Interesting that such a small resivoir can produce so many shots….even at that low of a velocity.

    Is it fairly quiet?

    twotalon


  4. Twotalon,

    It seems VERY quiet, but I was so close to a heavy steel trap that the impact noise made it impossible to judge accurately. Perhaps when I test for the best pellet I can tell.

    B.B.


  5. B.B.

    That’s is a lot of valve lock!!

    But makes the gun easy to fill!

    I hope you find that when you find the right pellet, that it will also lower the difference in the fps… lighter or tighter fitting pellets mixed into the group would cause some of the variance wouldn’t it?

    I shoot JSB heavies 10.2gr. in some of my springer and CO2 pistols, and they seem to steady the fps, and give good groups, even if they are just a little slower than JSB 8.4 gr. which is my second choice in the more powerful pistols (400-500fps).. my guess is that you’d see only about 20fps difference with the 10.2 JSB.. in maybe 70-80 shots.. maybe you could try that?

    On the fill adapter.. I attached a male foster fitting to the end of it and I put the adapter on the gun and then hook up the female foster on the hose..
    It’s much easier to find the slot and put the adapter on, then hook to the hose.. also your not fighting the angle and messing up the inside of the adapter, which happened to my first one on the .177 AAs410 that I’ve shot so much now.. since I’ve got other AA guns, I’ve got several adapters and the second one is very clean and works great still..

    Can you try it out at 25 yards too?
    Some of us would want it for plinking or small pest control.. would it be good for that too?

    Wayne,
    Ashland Air Rifle Range



  6. BB,

    I’ve looked at some of the past tests for 10M pistols and, in this price range (and lower), do you have any feelings as to what would be your choice in pistol to start with? It appears to be between the IZH41M, the Alfa,and the Avanti from what I can see. Is it better to go CO2, PCP, or single stroke pneumatic?

    Fred


  7. Fred,

    That’s always going to be a tough call. I shoot a CO2 gun, but I don’t recommend it for anyone.

    If I were to get another pistol I would buy a used PCP and prepare to spend about $700.

    Of the guns at this price range, this might be the best, but please allow me to finish the test.

    B.B.


  8. Fred. I recently purchased the Gamo Compact. In the price range I was looking it came down to that, the Avanti or a used IZH.
    I went with the Gamo partly because of price but mostly the grips.
    I found that, though the Avanti is accurate and well made, the grips are detrimental to learning and maintaining a consistent target hold. I’m sure it would be good for informal target shooting, but in my opinion fails as a 10m trainer.
    I’ve been to a number of ISSF pistol events and am amazed at the lenghts these people go to maintain a consistent grip…in the entire course of fire they never put the pistol down, nor it seems do they shift the pistol their hands.
    CowBoyStar Dad


  9. Thanks for that input, CBSD and yes, BB, I can certainly wait. I’m still planning on getting out to the Ohio Garage Sale (OGS) and have added a 10M pistol to my list of “nice to haves”.

    I’m looking forward to the Crosman hotdogs!

    Fred


  10. Dr. G,

    Two at a time…

    When it comes to odd tests, I would guess that I’m in the lead.

    My findings:
    Round balls are a little easier to load two each and since I have never found them as accurate as a pellet, this is an area they excel in. (not BB’s – lead balls)

    As twotalon stated one issue is accuracy. It seems silly to use a scope aiming exactly at the “10” but actually hitting the 7 and 8 ring on opposite sides. So anything with glass is out and other then testing, target shooting is a thumbs down.

    Energy is always less with two pellets or two lead balls, at least in a Springer. This is not a huge surprise as energy usually declines with just a single heavy pellet. I know some of the tuners feel too heavy a pellet can damage a rifle, but not all agree. So play at your own risk.

    The conclusion of my testing – only two rifles I owned ever showed the slightest use for a double load. The first was a Patriot in .25 cal. I had a peep sight on it and felt that the two copper coated rounds would be effective on a speeding bunny. The two hefty balls of lead managed just over 20 ft lbs combined and printed very nicely out to 15-20 yards. A single lead ball gave about 23 ft lbs. (the best single pellets went 26-28 ft)

    The second double gun was a smooth bore Diana 25 circa 1933. Once again a single pellet gave the best accuracy and energy, but two lead balls stayed close far enough out to make instinctive or snap shooting fun. The rifle had no provisions for mounting a scope so range was limited, and it was an interesting diversion.

    Admittedly, both applications were more of a way to use up the lead balls. I would probably never seek this out intentionally.

    My latest “who cares” test is a comparison of a Daisy 499 circa 2007 vs. a Daisy 99 Champion made in 1967. I picked the 99 up at a flea market last week and it is in 95% + condition. It looks to be about the same age as the 499 instead of 40 years its senior.

    Volvo


  11. Chuck,

    You have crossed over. Congratulations. How’s the trigger on the Air Force rifle. I’ve heard criticisms, but it can’t be that bad with the results you’re getting. Does everyone remember that this is the Week of the Marauder?

    B.B., while looking around at the Feinwerkbau rifles, I see there is a top dollar rifle which is a single stroke pneumatic. That would seem to eliminate all of the hassle of testing for power curves. Would such a rifle be a legitimate Olympic contender or are they exclusively PCP at that level?

    Matt61


  12. Matt,

    Yes, single strokes are used in the Olympics for both rifle and pistol matches. They are just as accurate as PCPs.

    Some people feel they are too much work during a match, but you never have to look for air, either.

    B.B.


  13. B.B.,
    The one area I have yet to try is a ten meter target rifle.

    A brand new purchase is not the cards at this time, so I have been looking at the various used FWB 300S’s or a FWB C62 CO2 Match Rifle.

    The C62 is about $100 more than the older 300S’s.

    Any other contenders you would consider?

    Which would you pick as a first and only?

    Volvo


  14. Matt,
    The trigger on the Talon is just right for me. I have no complaints, yet. I have not adjusted it, but use it as it came.

    There is hardly any first stage travel. I know there is some but it’s so little that it’s almost non-existent. I don’t have a gauge but it takes very little pressure to trip the second. I don’t know what happens after that because I’m too amazed to notice. I think it’s entirely possible that, with all my other rifles, previous lack of consistent success is due to trigger function. However, I seem to be able to maintain the Talon on target better, also, and time my heart beat better with it.

    I shot nine targets this morning testing out pellets, and six of them had smaller than 1/4″ groups of five, ctc. Of the remaining three, one was 1/2″ using Crow Magnums, the other two were 1/4″ except for one flyer each out to 1/2″. The flyers were caused by me getting the yips, I’m sure.

    I’m using only one a bean bag to rest my forward hand on, gun resting on top of of hand. The CO2 bottle is tucked into my shoulder. And, I’m shooting 10yds on the lowest setting.

    I’ve had to make one modification to the gun. I took a pair of black cotton socks, one inside of the other and slipped them over the CO2 bottle. Dang! That think gets cold on my cheek. The double socks takes care of that and really doesn’t look that bad, either. I noticed the PCP air bottles have a foam cover. I don’t know why the CO2 ‘s don’t come with one you can slip on. I suspect they need it more than the air tanks do.

    -Chuck


  15. Volvo,

    Don’t overlook a Walther LGR single-stroke. Also a Diana 100 single stroke, though they are hard to find.

    The Gamo 126 single stroke is problematic and not the most sophisticated, but it’s often the cheapest. When they work they tend to work well.

    A Diana 75 is another goodie. But it, too, can be problematic. Get one that works because resealing is expensive.

    B.B.



  16. Twotalon,
    Ahh, maybe I haven’t totally crossed over, yet.
    I got the .177 and CO2 for two reasons: Illinois only allows .177 700fpsmax without having to deal with an FFL store(CO2 max for Talon SS is 700fps, convenient, eh?); 99% of my shooting will be in my basement range so even 700fps is too much, I dial down to minimum (400?).

    Also, I got CO2 because the the scuba fill clamps were back ordered and that’s the way I wanted to go and I didn’t want to wait. But now that I have a Talon SS I can upgrade to .22 in the future if I want to and I can upgrade to air also and have four possible configs(plus more for the different barrel lengths available).

    However, as it stands now, it will be cheaper for me to stay with CO2. I use a 12oz tank and here CO2 only costs 25 cents an oz. An extra CO2 tank costs $20 plus the $3 fill charge. The Talon SS advert says over 1,000 shots per tank (low setting I’m sure, which I’m using).

    To convert to air now will cost me over $300* plus scuba fills. That equals 100 CO2 refills which equals:
    1,000spf * 100f = 100,000 shots total.
    100,000st/500sptin = 200 tins. I’ll need a new gun before the break even point, I think.

    *Air tank $170, fill clamp $62, Scuba tank $140 (or pump $200).

    -Chuck



  17. CJr
    Looks like you made a good choice (.177 and CO2)for indoor shooting if you can slow it up as much as you want to.

    twotalon



  18. Chuck,

    That trigger sounds good to me. So much criticism out there about products is just a mystery. Improving one’s heartbeat is quite a standard; we’ll see how the Marauder compares. Make sure you keep using black socks for the fill tank. :)

    B.B., maybe those timing their heartbeats are bothered by the work of a SSP, but I don’t think I would mind. As compared to the 12 lb. effort of the IZH 61 which is hardly noticeable, the 17 lb. effort of the Feinwerkbau doesn’t sound like much.

    Matt61


  19. Matt61,

    It’s not just the effort.. It’s taking ones concentration off the target.. and having to “reset” oneself for each shot.. the less resetting the better..

    Wayne,
    Ashland Air Rifle Range


  20. Wayne,

    That’s true although the hassle involved with single shot bolt-actions has not prevented them from being preferred for pure accuracy. I see your point though.

    Matt61


  21. G’day BB

    “Maybe I can blog a homemade repair fixture that will help you with your job. Would that help?”

    That would be great!!!

    Cheers Bob





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