M1 carbine Keyholing

[sixpointfive]

I have an M1 carbine that shoots 1" groups perfect at 25 yards using jacketed bullets. When I went to shoot my 130 Lyman 311410 sized .308 with 12gr of H110 they key holed on target. What is going on here, please help.

[leadman]

.308" is probably too small. I size .310" or .311" depending on which carbine I am feeding.

The throats are normally pretty large on these so if you size to .308" you are blowing gas by the bullet.

[Shiloh]

+1

.308 is undersized. Size larger and report back.

Shiloh

[sixpointfive]

I do have some sized .309 that I am going to try with 1 grain less powder (11gr H110). I wish I had a .310 sizer. Lee makes a .309 and a .311. Do you guys think the .309 is big enough ir should I go with the .311?


Matt

[Shiloh]

I just looked, LEE doesn't make a .310. Unbelievable!!

Try the .309 If it doen't work it is a cinch to hone it out .001. Fine emery (400 grit)paper in a slotted nail or dowel. Polish with flitz, simichrome or other metal polish.

Have you slugged the bore?? If it is .3085 or .309, then the .311. I'm still surprized LEE does not make that size. A very common .30 cal size.

Shiloh

[jimb16]

Let me guess....you have a Herlo barrel on the carbine. On the bottom of the barrel it is marked 5557154 HC or 844/8416HC. If so, that is your problem, not the bullets. If you have either of those markings, you will NEVER get ANY bullets to shoot well because the barrels were bad. The Gov. rejected every last one of them!

[sixpointfive]

.309 and 11 grains of H110 still produced key holes. I am going to try and size some .311 and give that a try.

[Larry Gibson]

I had the same problem with that bullet in a couple M1 Carbines. I beleive the problem has to do with the 18 od 20" twists and the long and heavy 130 gr bullet. I got keyholing with nthsoe 2 carbibes regardless of what I did or the velocity. Even wit those that did stabilize that bullet I never got decent accuracy over 1600 fos. Best load was 12 gr of H4227.

Larry Gibson

[Patrick L]

I would also try to shoot a few unsized, lubed with LLA. Don't worry if your loaded round looks a bit "pregnant", as long as it chambers without undue resistance.

I think fatter is better. My molds drop boolits almost .312, and they shoot great. I have also had great luck sizing them to .311, but less work=more trigger time.

[jimb16]

I've shot the Lyman 130 gr plain base in a large number of carbines and never had a keyholing problem in any of them!? I don't know what you guys might be doing wrong. My velocities are around 1500 fps and the bullets are cast hard. I usually use IMR4227 or IMR 2400, but have also used H110. Oh yeah....I also size mine .309.