M1 carbine clones

[Blowpipe Sam]

My most fervent wish when I was twelve years old was for a Crosman M1 carbine replica.  That wish was never fulfilled and there have been quite a few air guns in my house in the years since.  So when I saw the new full auto Crosman M1 (M2?) quasi-replica it piqued my interest.  Wallymart was selling them for $120 before Christmas and I figured I'd pick one up after the holidays if I still had any surplus income left.  Well I actually got a little cash for Christmas and made hasty hoofbeats over to the PA website to order some pellets.  While there I compared the Crosman M1 with the Air Venturi/Springfield armory version.  What do you know PA has the AV/SA version on sale and there's a refurb offer and a 25% discount code!  Less than $80 and free shipping?  Sold.
Got it today and I had a few minutes to play with it before it got too dark (and cold!).  First impressions are positive.  The gun is a very authentic replica. You'd never mistake it for a real surplus M1 but it would easily pass for a current production Chiappa.  I only had time to shoot two magazines worth of BBs but functioning was perfect.  After twenty eight BBs and a dozen dry shots the cart was empty.
I'm going to post my impressions here as I play with this gun over the next couple of weeks.  I invite others who have purchased the AV/SA M1 carbine to comment and anyone who has the Crosman full auto version please chime in.

[Blowpipe Sam]

I must say that AV has taken authenticity to the extreme.  The Achilles heel of the original M1 carbine was its magazine.  The heart of the AV M1 is the valve and the valve is part of the magazine.  Let's just say the magazine is a bit finicky.  The first magazine ran fine.  The second dumped all its gas as soon as I tightened the cap.  The third cart leaked for about three or four seconds and then stopped.  It ran fine for 28 shots.  The fourth cart dumped all its gas immediately.  The fifth leaked until I inserted it into the gun and pulled the trigger twice.  It then ran fine for 28 shots.  The sixth and seventh carts dumped but the eighth cart leaked for ten seconds or so until I could insert it in the gun and shoot twice.  Now the gun is leaning against the rack participating in a leak-down test.  We'll see if it's holding gas tomorrow.

One nice thing about these magazines is you can drop them in a pot of water for a leak test.

Tomorrow I'll try a chronograph test if the outside temperature is high enough.  A feature of this gun that I didn't see anywhere in the advertising or the reviews is the very authentic manual bolt hold-open pin.  I'm thinking about modifying it into a bolt hold-closed pin as well.  Here's why.

The "bolt" on this gun is in two pieces.  A white plastic tube is the bolt itself.  It slides back and forth inside the "bolt carrier".  On the bottom of the white plastic bolt is a rectangular port that aligns with the transfer port (for lack of a better term) on the top of the magazine.  When the trigger is pulled the hammer strikes a firing pin which is aligned with the valve stem in the magazine and not the bolt itself.   The valve releases gas which passes up through the transfer port and into the interior of the white plastic bolt.  This bolt is open at both ends.  One end is the "bolt face"  which pushes the BB into the barrel leade and seals against the breech.  The other end seals against the end of the bolt carrier .  Gas enters the bolt through the transfer port and pushes against the BB in the barrel at one end and against the end of the bolt carrier at the other.  The BB, having much less mass than the bolt carrier, flies out of the barrel.  After a little delay caused by its mass and the (light) return spring the bolt carrier starts moving to the rear while the "bolt" telescopes and remains pressed against the breech.  After the bolt carrier has moved about two inches to the rear it engages a shoulder on the bolt and pulls the bolt rearward with the bolt carrier.  Once the bolt moves about a half inch backwards it is no longer aligned with the transfer port on the magazine and the no longer pressurized the bolt snaps backwards into the bolt carrier pushed by a small spring.  The bolt and bolt carrier continue moving backwards together until the hammer cocks.  The bolt and carrier stop and start moving forward together driven by the bolt return spring.  A small protrusion on the bottom of the bolt slides between the feed lips of the magazine and pushes another BB into the breech ready for the next shot.

A lot of gas is going out the back to push that bolt carrier backwards.  If you could lock the bolt carrier forward all that gas would have to go out the barrel.  Just thinkin.

[Blowpipe Sam]

I loaded and shot three carts in a row this morning averaging thirty shots per cart.  It's cold here in Nawth Flarda today.  Temps were in the low fifties so not an optimal day for shooting a gasser.  The magazine is made from a solid chunk of metal and it acts as a heat sink.  Warmed to about 70 degrees the magazine is good for about seven shots at today's temperatures before the velocity starts to drop.  Placing the magazine inside my jacket kept it warm enough to shoot four or five shots before putting it back in my pocket.

Hand loading single 7.9gr CPHP was not a success.  The pellet fell into the breech and fit snugly into the leade with a little encouragement from a toothpick.  A little too snugly as it turned out.  The AV/SA M1 carbine was unable to blow the pellet out of the barrel.

[Blowpipe Sam]

The front sight is held on by one tiny grub screw.  Mine was loose when it arrived so I tightened it.  This evening the front sight almost fell off the barrel.  I put a dab of blue lock tight on the screw and tightened it again.  I also took the opportunity to tighten up all the mounting screws.  Everything feels more solid now and there's no rattle anymore.

[bantam5s]

Did you get the regular one or did you pay up for the real wood furniture?
I payed up for the real wood.

[Blowpipe Sam]

I got a refurb with the synthetic furniture. I originally planned to gift this to my brother but the reliability is poor.  I think I'll keep it to be a "party gun" when guests come by and we have a big shooting session.

[bantam5s]

I got a refurb with the synthetic furniture. I originally planned to gift this to my brother but the reliability is poor.  I think I'll keep it to be a "party gun" when guests come by and we have a big shooting session.

I had to get the wood because I truly dislike plastic, but sort of regret it now just because of how much I payed for a gun that proved not to work.

[lillysdad621]

I am seriously fighting the urge to get the Crosman... they are so cool.

[bantam5s]

I am seriously fighting the urge to get the Crosman... they are so cool.

They just don't really do it for me, because they're not realistic enough and not really priced low enough to justify the compromises.

It was bad enough for me that the gun I bought had to be Springfield Armory branded and based more off a modern reproduction from Chiappa than off an original with say Inland markings.
I'm just care too much about the details I guess.

[Blowpipe Sam]

The Crosman is not a very accurate replica but the magazine and feed system looks like a much better proposition than the picky AV/SA magazine.  The Crosman takes two carts and the magazine looks a lot more reliable.  The AV/SA gives up a lot of functionality for authenticity.  Crosman went with a general resemblance to sell a cheap full-auto BB gun.  I may still get the Crosman M1 (M2?) just so I can play with the full auto feature.      

[lillysdad621]

Crosman M1 (M2?) just so I can play with the full auto feature.

+1... i know!!!

[Blowpipe Sam]

I’m going to go out on a limb here and suggest that semi automatic blowback operated co2 propelled BB guns do not operate efficiently in cold weather.

I sat out on the river bank in the sixty degree sunshine and the AV/SA M1 ran flawlessly for three cartridges.  I was only getting about 25 shots per cart but the accuracy was eye opening.  I was eliminating floating leafs at fifteen yards and even longer ranges.  Until the wind started blowing.
I took the gun back to the shady part of the yard and immediately began having problems. Failure to cycle fully and dumping the cart.

Conclusion.  If the CO2 is too cold the action will not cycle all the way to the rear.  The “firing pin” doesn’t knock the valve open.  It presses it open and holds the valve stem depressed until the bolt moves backwards enough that the pin is no longer in contact with the valve stem.  If the bolt doesn’t move far enough to the rear (see above) the pin will continue to depress the valve stem until all the CO2 escapes.

[bantam5s]

I’m going to go out on a limb here and suggest that semi automatic blowback operated co2 propelled BB guns do not operate efficiently in cold weather.

I sat out on the river bank in the sixty degree sunshine and the AV/SA M1 ran flawlessly for three cartridges.  I was only getting about 25 shots per cart but the accuracy was eye opening.  I was eliminating floating leafs at fifteen yards and even longer ranges.  Until the wind started blowing.
I took the gun back to the shady part of the yard and immediately began having problems. Failure to cycle fully and dumping the cart.

Conclusion.  If the CO2 is too cold the action will not cycle all the way to the rear.  The “firing pin” doesn’t knock the valve open.  It presses it open and holds the valve stem depressed until the bolt moves backwards enough that the pin is no longer in contact with the valve stem.  If the bolt doesn’t move far enough to the rear (see above) the pin will continue to depress the valve stem until all the CO2 escapes.

They absolutely have these problems.
My 2240's, 2400kt, Sheridan E, S&W 79G Crosman 180, and Crosman 400 do not have this problem.
My co2 revolvers don't have this problem all that much either.
The M1 and 1911 absolutely do though.
My M1 would even do this in the sun on a 110° California summer day.

[Blowpipe Sam]

Warmer temps today.  I got out the chronograph and generated some numbers with the M1.  I shot two magazines of Crosman Copperhead BB’s (28 shots) at ambient temperature (64F) pausing to let the gun warm up between shots.  Velocity started at about 350 fps and peaked at 378 fps after twelve shots.  It fell to 281 fps by shot number 28.

The second cartridge I removed the magazine from the gun and warmed it on a heating pad between shots.  I shot two ten shot groups and one eight shot group starting at 407 fps and declining to 397 fps by shot number ten, 347 fps by shot 20, and 277 fps by shot number 28.  At high pressure this gun does suffer from valve lock.  It manifests as short cycling by the bolt until the pressure drops.  At velocities above 385 fps the gun had to be cycled by hand between shots.

Everything ran as advertised.  Unable to find my bottle of air rifle lubricant I grabbed a bottle of 3-in-1 oil and lubricated the tip of the first cartridge.  The cartridge sealed perfectly  as did the next two and the gun functioned as it should.  I’m switching to 3-in-1 for this gun since it seems to be the solution to cartridges not sealing.