Dangers of cast bullets in m1 carbine?

[W.R.Buchanan]

Let me add my .02 to this BS. With 50,000 psi behind it, nothing is going to stick around very long in a gas system on a high powered rifle.

I have heard this particular line of BS for the last 30 years, but so far have not been able to actually see it take place,, and I have looked.

I concluded it was a crock around 1990 when I first heard about it.

A Water-Jet Cutting machine will cut steel with less than 50,000 psi and just plain water. A little lead wouldn't even have a chance.

I consider this Myth "Busted!!!"

Randy.

[jimb16]

OK! I'm going to throw my $0.02 into the ring. I've owned 20 carbines over the years (3 right now). That included a registered M2 carbine. I shot cast in every one of them, including the M2. Only 1 of them ever had a problem with cast bullets and it was a Saginaw Gear. It had a rough spot on the edge of the gas port. It did shave lead into the gas chamber. Even then, it never caused the piston to stick out preventing the slide from moving fully forward. The vent would plug up before that happened preventing the piston from operating. This story, to me, is a bunch of B.S. Yes, I did have to remove the piston on that carbine and use a small drill bit to clear the leading in the gas port. But that was all. No significant lead build up was to be found in the expansion chamber and what was in there was easily cleaned out with solvent used to remove powder fouling. At least half of all carbine ammo that I shoot is cast loads and I don't have any problems. I never need to remove the gas piston to clean the piston chamber. It just doesn't lead up. BTW the carbine operates at a max of 40,000 PSI, not 50,000. (minor technical point)

[biffj]

I've been working on machineguns for a long time. I have had some experience with the problem in the M2 carbine but not the M1 as I don't work on them. In all the time I've been doing this I've had 2 M2 carbines come in the shop for failures to function. Both guns had lead in the gas system that plugged the flow or jammed the piston. Both had a lot of lead in them but neither stopped the piston from going forward. It wasn't too tough to clean them out once the pistons were removed. One piston was especially difficult to get out as it had lead holding it in place but we got it out and cleaned up. The big difference in the M1 and M2 for shooting lead is heat. A guy who dumps a couple 30rd mags at 600 rpm will take the barrel temp up to near the melting point of lead. With the heat applied to the bullet by the powder burning and the hot barrel there will be vaporized lead in the gas venting into the gas chamber where it will eventually cool enough to be a problem. Both owners of the guns we worked on said they had no issues the last time they shot their rifles, it was the next time they tried to shoot them that they would not function. The deposits cooled sufficiently to become a plug by that time. The carbine ammo isn't going to have 50k psi at the gas port and with no flow it won't remove any buildup. The gas system is a dead end so regardless of pressure things won't just work.

Shaving lead may be a myth but enough heat can cause its own issues. Back in the early 2000s when surplus ammo was really cheap there were a lot of issues with machineguns that were new and different and due entirely to poor management of triggers. Many guns were not ever intended to be run at the high rates some owners think is neat and fun. Things happen. The M1 carbine was never intended to be a machinegun and the M2 conversions had a lot of issues due to the adaptation. Just something to think about and maybe one of the sources of the myths about shooting lead in carbines?

Frank

[Win94ae]

Exactly what happened to my AK. Clean it out when it needs it. Took a few thousand. I don't think it is shavings, but lead, lube and powder residue.

[Texas by God]

I didnt make it through 50 rounds because it was so dang hot. Ringing a 6" gong offhand wasnt hard at all. I do need to up my powder charge a bit. Great function but some sooting of cases and blow back of gas was noted. My 110 jsp loads are factory speed and no problem.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[Larry Gibson]

biffj

Pb's or GC bullets used?

My experience over many years shooting cast bullets in numerous M2s resulted in no plugging of the gas port at all. I had 25 M2 Carbines in my arms vault (SF Company and an indoor range where I shot them often along with outdoor ranges on Fort Lewis. I used mostly the 311359 GC over H110 for 1850 fps. several got hot enough dumping 30 round mags full the shooter need a glove to hold the hot [and many times smoking] forends.

[elmacgyver0]

If it is actually shaving lead it will most likely shave copper too.

[jimb16]

Larry, I had the exact same experience with my M2. Smoking stock and all and no leading. But I didn't leave rounds in a hot chamber either. Didn't want any cooking off!

[dogmower]

I've shot just short of a Bazillion rounds of cast through my M1 and M2 carbines. Never a problem, in fact they generally shoot better than jacketed. So, no, cast is not a problem.

[car16]

I have shot thousands of cast both plain base and gas check no problems

[mfraser264]

Using the RCBS 115 round nose bullet with gas check cast of Linotype have shot 2,000-3,000 through M1 from Universal out of Florida. Only problem was case lenght and I figured that our as a teenager. Keep the cases to spec on the length or they will not chamber. Also sized the bullets to .310 driving it with H110. At one time probably had every head stamp of brass there was and it performed very well. I remember my father saying how well the loads worked and he qualified in the armed services with a M1 Carbine. So yes it is viable option and cost efficient considering most of the tie the bullets impact a sand bank so why burn up more expensive jacketed bullets when cast bullet work just fine.

One other tip when trimming, may need to reduce the .30 caliber pilot down a few thousands of an inch to compensate for case taper.

[roverboy]

I've never heard of this personally but, did see a Thai M1 carbine made by Howa, that had a piston get stopped up with something and come loose. I don't think it was lead shavings. My Inland has a band around it to secure it in place. The Howa Thai was soldered in place.