Rimfire vs PCP

[Guest]

I own quite a few match grade 22lr rifles including a custom AR platform I've reached to 600yds with consistently. At 50yds, the comparison is fair without a doubt. And even at 100yds the edge can and does favor the pcp. BC and grain weight isn't a deal breaker to accuracy at those distances. I'm a long time powder shooter, and shoot every day. Until recently, there wasn't anything else. Now I'm really leaning more and more to air. I think it's a matter of time before we see pcp guns reaching the insane distances achieved by powder. Slugs are the future, and I think once they are 40grains they will have the ability to really show what they can do. The BC isn't there yet on what is available. And air hasn't gotten the to the point of supporting those 40gr chunks with any shot count yet, yet.

Yep yep.. Let me introduce 222rem 12,6" twistrate rebarreled spa M10 pushing 50+ grain pills at 110+FPE with 2900psi with BC of 0.16-0.21 depending what you feed.

Air is actually really far from being capped.. If manufacturers would be interested you could build 40gr 22LR like bullet shooter and get like 80++ 75FPE shots out from 250bar 500cc bottle. Atm biggest limitation is eather manufacturers dont want to make that or than they simply dont understand bigger than caliber channels equal = more power, less air consumption. I personally think manufacturers might fear legistlation if they build pcp guns with similiar performance as 22LR.

Atm these guns are just toys of really rare and few ppl. 

 

[thomasair]

Just to bring some mathematics into the discussion ....if you had a 500cc 250 bar bottle and got fantastic efficiency (1.5 fpe/ci) you might get 50 shots at 75 fpe shooting down to 2350 in 22 caliber. If you got 1.5 fpe/ci....your velocity spreads would not be very good over the fill. Maybe good enough for hunting, but not good enough for target work even at 50y. 50 shots is a very long way from 80 plus.

Mike

 

[Guest]

Just to bring some mathematics into the discussion ....if you had a 500cc 250 bar bottle and got fantastic efficiency (1.5 fpe/ci) you might get 50 shots at 75 fpe shooting down to 2350 in 22 caliber. If you got 1.5 fpe/ci....your velocity spreads would not be very good over the fill. Maybe good enough for hunting, but not good enough for target work even at 50y. 50 shots is a very long way from 80 plus.

Mike

That spa above there did that with 110bars with almost full valve lock due new poppet and not enough hammerspring. With previous poppet and hammerspring backed down it was capable of doing 10shot string at 85fpe with even shotspread and 1100cc per shot. Even with that would equal 63,63shots from 250 to 110 and dropping power by 10fpe and increasing air cylinder size from 250 to 500+cc (bigger aircylinder usually boost ur performance bit also) Im fairly sure its doable. If you would want to have such build with efficiency and regulated u would probably want to have 200cc plenum at 100-110bars and 500bar at the end. It is amazing how efficient full power builds are if you tune them down. Air channel size is the only limiting factor. I have mine at 6,5mm and valve larger due poppet axel taking some surface area. Only squeezing part is at barrel port and thats oblong shaped towards muzzle while bolt backs away and gives 100%free flow. The reason why they are more efficient when tuned down is the fact you get biggest possible pressure strike due better faster flow and more volume before bullet but if tuned down you dont keep valve open for too long and actually push more FPE with less air. Biggest pile of junk you read on most forums is that you dont gain anything by increasing airways to bigger than caliber.. I personally dont see any reason to stay sub caliber unless you want to push really light projectiles. That 80+ might be bit optimistic yeah but I cant really say before its done. I might try to get dropblock for 500cc bottle machined for that and regulate that 250cc tank and see what happens. It surely is on my to do list. 

 

[thomasair]

Operating with very low valve openings, high flow and high pressure gets you poor shot spreads. The slightest variance in friction in the strike mechanism will result in big velocity differences. Rifles set up this way are also extremely sensitive to temperature change as well.

I’m sure 2.0 efficiency can be achieved...but highly doubt it can happen with a good velocity spread.

At 50y for BR I need 10fps spreads or less to do well, and I need that to occur for at least 40 shots in a row every time.

I’ve never seen super efficient guns be accurate, and Ive never seen super accurate guns be efficient....although I’m sure I haven’t seen everything.

Mike 

 

[Guest]

Operating with very low valve openings, high flow and high pressure gets you poor shot spreads. The slightest variance in friction in the strike mechanism will result in big velocity differences. Rifles set up this way are also extremely sensitive to temperature change as well.

I’m sure 2.0 efficiency can be achieved...but highly doubt it can happen with a good velocity spread.

At 50y for BR I need 10fps spreads or less to do well, and I need that to occur for at least 40 shots in a row every time.

I’ve never seen super efficient guns be accurate, and Ive never seen super accurate guns be efficient....although I’m sure I haven’t seen everything.

Mike 

Yes you are right about super high pressures short valve openings for sure. Also it would be impossible to keep ES small without regulator and with 140bar pressure range. Thats why Im going with route of using that 250cc stock cylinder that can make that power and regulate it. Shall see if I get it done at somepoint would be interesting to see. Point was anyways that current platforms are far from being maxed out and you can have fairly decent shot velocity using 22LR like bullets that are provided by RWS with relatively low operating pressure while gaining high efficiency. Can you do that with under 100cc of plenum space. I highly doubt it. Altaros M24 will be interesting to see if it ever hits market 10shots with 75joules and only 12cc of plenum space but I badly fear that application will be super high pressure. My estimate for that gun is that plenum and valve are located in bolt to get zero space between and have dirrect flow application. Anyhow its really unlikely any big manufacturer start to make one before its allowed to use slugs on BR and before someone clears table using 22lr like or better bullets before that its just too big risk of getting bad attention and getting stuff legislate and that for sure might kill big part of the sport. 

 

[Exodus]

Yep yep.. Let me introduce 222rem 12,6" twistrate rebarreled spa M10 pushing 50+ grain pills at 110+FPE with 2900psi with BC of 0.16-0.21 depending what you feed.

Wow, never knew that existed. Now that's the kind of airgun I would like to own. Something that truly is high performance. Thank you for showing it off. Dang, that's cool. 



How does it shoot? I'm honestly interested enough I may try and do something like this. I have a budget gun that might have to give their luge in the name of science. 

 

[Guest]

Yep yep.. Let me introduce 222rem 12,6" twistrate rebarreled spa M10 pushing 50+ grain pills at 110+FPE with 2900psi with BC of 0.16-0.21 depending what you feed.

Wow, never knew that existed. Now that's the kind of airgun I would like to own. Something that truly is high performance. Thank you for showing it off. Dang, that's cool. 



How does it shoot? I'm honestly interested enough I may try and do something like this. I have a budget gun that might have to give their luge in the name of science.

Its still on testing phase and not as well as I would like to. My goal is sub 30mm@100m with 10shot groups.. Atm its mainly task of finding right bullet, speed, pressure range for 100m but Im middle of house reno and only have 50m range at home so havent shot it for a long time at 100m.

That is 10shots at 50m but as we all know it dosent tell much about 100m. 

 

[Exodus]

Its still on testing phase and not as well as I would like to. My goal is sub 30mm@100m with 10shot groups.. Atm its mainly task of finding right bullet, speed, pressure range for 100m but Im middle of house reno and only have 50m range at home so havent shot it for a long time at 100m.

Very nice for beta testing. Shows some promise for sure. I'm assuming you used a 222 Rem barrel blank on the m10 and machined from there? I think I may go somewhat that route. Think I might use a Clint Beyer barrel, SS lined aluminum to keep the weight down and I'm not sure what reg and bottle. Maybe a gauntlet bottle and modded reg. Not sure on the receiver. Haven't cracked open a Gauntlet to see what it looks like. Awesome build so far. I'm very interested where this leads you.

 

[Guest]

Yeah it was LW 222rem blank 635mm long 26mm thick.. Got it cheap but turning it down is horrible lol. I would alltho recomend to go with 12" or faster twist, 12,6" have proved to be fair challenge to find suitable projectiles. If you want to stay at 40gr+- range I would take 22LR liner and wrap it up on carbon fiber. I dont know how gauntlet is but if you want to have that 40gr+ at 950fps you surely need massive plenum if you regulate it and I dont think there is such a gun maybe jsar raptor? 

 

[thomasair]

Here is the Thomas HP tether gun, and the HPX dual plenum BR gun.

The tether gun has the reg in the nose, so the entire tube is a plenum.

The HPX is self contained and has two plenums of about 120cc total.

Im using rimfire barrels to shoot 40-43 gr slugs.

Here is a 50y BR card shot yesterday.

Mike.

 

[JungleShooter]

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In awe. 

Very cool, Mike.

Matthias

 

[steve123]

You're making it look easy Mike!

That heavy barrel looks RAD!!!

 

[Centercut]

Wow, looks like you're ready to compete with the Unlimited Class rimfire shooters. Is that a new one piece rest that you made for the gun? Do you adjust windage and elevation from the rear? 

 

[Corvid_hunter]

Groups are not particularly meaningful unless you are shooting for group size.

Score shooting tells the tale.

If you have two guns that group equally, but one is 4x more wind resistant...it’s not going to be much of a challenge between the two on anything but a dead calm day if the shooters have equal ability.

Mike

I get what you are saying, especially when it's repeated often enough, but not everyone shoots for score. Some people like to shoot for group size.

 

[tibor]

awesome post..that keeps giving..super interesting

 

[thomasair]

Thanks,

The rest is a PQP lite. https://www.killoughshootingsports.com/adjustable-rifle-rests/729-precision-lite-1-piece-rest-by-pqp.html

Wish I had bought one 5 years ago. It’s about perfect for air. It weighs about 1/2 of my two piece setup and I can carry it to the bench with one hand, plop it down and be ready with no attention to alignment or setup. It’s not any steadier, but it’s sure less fuss. 

Still a ways to go to be competitive with unlimited Rimfire guns. They can average cards like this.

Mike 

 

[Guest]

Here is the Thomas HP tether gun, and the HPX dual plenum BR gun.

The tether gun has the reg in the nose, so the entire tube is a plenum.

The HPX is self contained and has two plenums of about 120cc total.

Im using rimfire barrels to shoot 40-43 gr slugs.

Here is a 50y BR card shot yesterday.

Mike.

Nice rigs man. Thats ideally the way this sport should go and will eventually get there!

 

[thomasair]

Jiikuu.....we have started a sanctioning body for 50y BR shooting. There is a slug/Rimfire class and your gun would be perfect for it. The power cap is 100fpe to keep things on par with 22lr rimfire...but you could easily detune slightly. Tethering is allowed, so guys should be able to get a lot of rigs working without a lot of custom parts. I can actually get 75fpe with my standard 20fpe guns by removing the reg and using a 3500 psi external reg on a bottle....small valve, ports, and all.

The website is www.National50.org. Get on board and get a club going to participate.

Mike 

 

[Guest]

Jiikuu.....we have started a sanctioning body for 50y BR shooting. There is a slug/Rimfire class and your gun would be perfect for it. The power cap is 100fpe to keep things on par with 22lr rimfire...but you could easily detune slightly. Tethering is allowed, so guys should be able to get a lot of rigs working without a lot of custom parts. I can actually get 75fpe with my standard 20fpe guns by removing the reg and using a 3500 psi external reg on a bottle....small valve, ports, and all.

The website is www.National50.org. Get on board and get a club going to participate.

Mike

Damn thats interesting! Sadly Im living in Finland and we have fairly few ppl shooting pcp airguns in here. Rules seem fair on that one.. There really is no reason not to allow tethering when its bench gun. In here hunting is not allowed with any caliber airgun so most guns here are built for bench and external reg. Will be interesting to see how close airguns will get to 22LR when there is no limiting factors for air. Atm smallest 10shot group @ 100m from airgun that Im aware of is 0,708" from drummen sinner and 22lr like bullet so on good day they defo should be able to give RF's decent opponent on br cards with matching ballistics. I hope that works out and we will see some nice results in future! 

 

[Khornet]

 Firing for group vs firing for score: I must be missing something. If your rifle doesn't 'group' then how can you depend on it for benchrest performance? Of course there's another order of skill necessary for benchrest, such as reading the wind and I'm sure much else besides, but until you can count on your rifle to put the projectile where it's aimed-including when you're deliberately not aiming at center to compensate for conditions- I don't see how you succeed. Seems to me if it won't group you have nothing to work with.