Springfield Armory M1 Carbine BB gun: Part 2
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Maxed out
- The test
- Problem number 2
- How to get the empty cartridge out
- Cartridge out
- Will the second cartridge seal?
- Oh, boy!
- Daisy BBs
- Air Venturi Dust Devils
- Hornady Black Diamond
- Smart Shot
- Shot count
- Trigger pull
There is lots of interest in this BB gun lookalike! Several of you have owned Carbines in the past, or own them now, and reader Bob M is following this report and also reporting on his conversion of an airsoft Carbine from semiauto to full auto. While full auto is interesting to many, I don’t think the Carbine is the right gun for it. The firearm had a not-so-bright history with Rock-N-Roll.The M2 Carbine that is select-fire is known to wear out more rapidly in the full auto mode. More rapidly than what, you ask? Than the standard semiautomatic Carbine.
The Carbine is a weapon that is stressed to the limits of the technology that was available when they were produced in the early 1940s. It’s funny — shooters today think the Carbine cartridge is weak, and its ballistics seem to support that opinion. But the cartridge is rated to 40,000 psi (CUP, for you reloaders) which is well beyond the pressure generated by the .357 Magnum cartridge.
Wearout happens first to the replaceable parts — particularly the extractor. The barrel goes next, getting too large just ahead of the chamber and also in the bore. Finally cracks can develop in the frame, and when that happens the rifle can no longer be salvaged, though its removable parts may be used again if they are still serviceable.
Of course we are looking at the M1 Carbine BB gun that has none of these issues. However, I don’t think making it full auto is something I will ever do. But I’m also an old fogey. You can do as you please.
Today we are looking at the power potential of this CO2-powered BB gun. The magazine holds up to 15 rounds and also contains the CO2 cartridge and the firing valve. So, in reality, the magazine is an essential part of the gun’s powerplant.
I will be testing a couple different premium steel BBs, and I don’t expect to see much variation in their performance. I will also test lead BBs and frangible BBs, just so we know the whole story. Let’s go!
The first step is to install a CO2 cartridge. The piercing cap is screwed in with the Allen wrench provided with the Carbine. That presses the CO2 cartridge against the piercing pin.
And that’s when it happened. My best-laid plans gang aft agley. When I tightened the piercing cap the gas hissed out very rapidly and never did seal. There are three primary possibilities when this happens. Either a seal is broken, or it is not properly seated (like an o-ring in its groove) or there is a piece of dirt on the seal that’s letting the gas escape.
Stuff like this happens to me all the time. Years ago I would just write a different blog and quietly fix the problem without telling you readers, but then I figured you must be going though the same things. It might be nice to see what I do with a problem like this so you have something to fall back on.
Here is what I did. Since this gun is brand new I reckoned the seals weren’t broken. There was probably either some dirt on the seals or they weren’t seated correctly yet. I would remove the empty cartridge and install a fresh one with some automatic transmission fluid (ATF) sealant on it. The new cartridge might blow the dirt out of the way and the ATF sealant might lubricate the seals, making them slippery so this could happen easier. If the seal wasn’t seated, another shot of CO2 might blow it into position.
Problem number 2
And that’s when problem number two reared its ugly head. The now-empty cartridge wasn’t coming out! It was stuck in the magazine and no amount of persuasion would budge it. A problem on top of another problem!
How to get the empty cartridge out
There are a couple ways to get the empty cartridge out. The quickest is to use a rare earth magnet of sufficient power to pull the cartridge out. Or you could drill a hole on the end of the cartridge and screw in a wood screw that will grab the cartridge right away. But I did something else.
I mixed up some JB Kwik, the 6-minute version of JB Weld, an epoxy that’s used for repairs. I cleaned the exposed end of the empty cartridge with acetone, then dropped the JB Kwik on the end and stuck the end of a machine screw to the blob of glue.
Once the epoxy set up I let it cure for about 4 hours, as I pondered how to hold the screw for cartridge extraction. I decided to put the shank of the screw in a vise and tap the top of the magazine with a rubber hammer. As I pondered this after the 4 hours were up I grabbed hold of the machine screw to see if it was glued tightly and, lo and behold, the entire cartridge came out of the magazine easily! Of course it did!
I think the cartridge knew that I knew how to remove it and just gave up. Inanimate objects will do that when they know they’re beaten!
Will the second cartridge seal?
Now that the magazine was clear it was time to put in the second cartridge. For the first CO2 cartridge I had used a Sig CO2 cartridge, so I tried an ASG UltraAir cartridge next. I did that because CO2 cartridges come in different dimensions and lengths. If one is too tight, another one may not be.
Before putting this cartridge into the magazine I dropped in many drops (20?) of ATF sealant. Then the cartridge went in and suddenly everything was together again. This one hissed for a second then grew instantly quiet, telling me it had sealed. That is the sound of a seal being blown into place. The test to see if the cartridge is pierced well is to pull the trigger, so I did.
I had forgotten entirely that this M1 Carbine has blowback. When I pulled the trigger there was quite a surprising reminder, in the way of recoil. This little airgun has some kick. Put that in the plus column! Now we can get on to the tests that are planned for this day!
First up are Daisy Premium Grade BBs. Ten averaged 413 f.p.s., but the spread was pretty large — from 386 to 435 f.p.s. That’s 49 f.p.s. The 386 was the only shot that was below 400 f.p.s., so it was an anomaly. At the average velocity this BB develops 1.93 foot-pounds at the muzzle.
Air Venturi Dust Devils
Next I tried Air Venturi Dust Devils. At 4.35 grains I expected them to be a little faster and they were. That average was 422 f.p.s. The spread went from 392 to 437 f.p.s., a range of 45 f.p.s. At the average speed Dust Devils developed 1.72 foot-pounds of muzzle energy.
Hornady Black Diamond
Next I tried 10 Hornady Black Diamond BBs. But the first string started at 366 f.p.s. and dropped to 258 f.p.s. by shot 7. I stopped because the bolt was barely blowing back. With three function shots fired before the test started, that was a total of 30 shots on the CO2 cartridge. I thought that sounded a little low, based on the Pyramyd Air description that says there are 40 good shots, so I changed the CO2 cartridge.
On the new cartridge Black Diamonds averaged 404 f.p.s. for 10 shots. The spread went from a low of 360 to a high of 418 f.p.s. That’s a spread of 58 f.p.s. At the average velocity Black Diamonds develop 1.85 foot-pounds of muzzle energy.
The final BB I tested was the Air Venturi Smart Shot lead BB from H&N. Ten of them averaged 333 f.p.s. with a 43 f.p.s. spread that went from 314 to 357 f.p.s. At the average velocity this lead BB developed 1.82 foot-pounds of muzzle energy.
The first good CO2 cartridge was in doubt after the second string, but this second cartridge is solid. I didn’t even fire a test shot to make certain the cartridge was pierced. I went right to testing. So at this point with 21 shots on the cartridge (due to me forgetting to release the magazine follower one time after loading), I recorded the next string of Black Diamonds that had averaged 404 f.p.s. at the start of the fresh cartridge. Here they are.
By the 32nd shot I could tell things were slowing down rapidly. The discharge sound was way off and the bolt was not coming back as hard. By shot 36 I felt I had to stop or risk jamming a BB.
You can pick the stopping place but this cartridge gave 32 to 36 shots before it was exhausted. So I’m calling the shot count 35 per cartridge.
I was surprised to discover that the BB feeds forward and stops in the breech. I assumed they were just blown out of the top of the magazine and through the barrel.
The non-adjustable single stage trigger breaks at 3 lbs. 6 oz. The break point is pretty consistent. It will be easy to shoot with.
So far I like the realism, the fact that the sights adjust, the strong blowback and that the trigger is light and smooth. I do find the shot count to be on the low side, which is no doubt due to the powerful blowback.
As realistic as this little rifle is, it’s going to be on a lot of buyer’s lists. I sure hope it turns out to be accurate!
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