M1 garand, Bullet jump/ reloading data

[ninjamasta04]

Hello guys, I just started reloading for my garand and i have a few questions.
The rifle was purchased from CMP 2 years ago, its a Special Field rated.
I made a few mesurements inside the camber using Hornady OAL gauge, and I got 2.805, thats where the lands starts.
Then I messured my 1st batch of reloads and it is around 2.719, and I found a few short ones, 2.713.
After that I got some PPU M1 loads and mesured them to be around 2.845.
#1 My main concern is that going to blow my rifle since the bullet jump is quite large.
#2 Factory PPU ammo seats the bullet way beyond the land, is it going to damage the rifling? Should I reseat these bullets closer to 2.805?

My 100 yards group is around 3 inches with factory PPU ammo.

[TJT]

Short oal rounds will not harm the rifle. When you run into trouble is when the bullet is forced into the leade and there is no free-bore. No free-bore causes excessive pressure.
Here's what to do: load a round with no powder or primer. Seat the bullet long enough to actually touch the lands when fully chambered. Now, extract the round (hopefully the bullet will still be in the case mouth and not stuck in the chamber). Now measure the cartridge oal. Set the die to seat the bullet .030" shorter. Load up some rounds and hit the range and see how she does. Just make sure the rounds are short enough that you can still stuff a full clip into the magazine. Shorten as necessary if too long to load into the magazine. If I remember correctly I make my cartridge oal's 3.330" which is .010" shorter than the published max oal of 3.340". I can't get to any right now to measure but I think my stated oal is correct
A 3" group at 100 yds with factory ammo is damn good.
Jon

[ninjamasta04]

Thanks TJT.
I have pulled the short load and reseated them according to Hornady specification OAL of 3.185", for 150 gn FMJ with canellure.
The numbers I posted earlier was mesured from the oval of the bullet not the tip. As stated my bullet actually touch the lands of the barrel at 2.805".
For these Hornady spec cartriges, I have stated the mesurements from oval to bottom of bullet is a sold 2.719" to 2.721". So my loads would be just short of touching the barrel lands.
As for the PPU factory OAL is at 3.319" to 3.325", they would be chambered way over lands and into the barrel it self.
So far i have shot about 500 rounds of PPU ammo with no signs of over pressure. Cant wait till I get the chance to go see what I got in the range.

[TJT]

The factory ppu rounds are fine as is. SAAMI specs are for the oal from case head to bullet tip, not the ogive (what you're calling the oval). I've shot thousands of rounds, both factory and home-rolled over the past 40 years and have never had problem one. I seriously think you're stressing over a non-issue. As long as you can load a full clip in the magazine you're good to go.
Jon

[ninjamasta04]

Just went to the range, not much improvement on those reloads. Going to come up with some more later

[HALOJM]

Just remember, your field grade M1 should hold 2-4" at 200 yds, will probably do better. Remember it was designed for minute of man. There are many things you can do to better that, but looking at your posts you should just shoot it and get to know it first.

[Smokey]

I might be wrong, but a special field grade should have a new Criterion barrel. Similar to a CMP special grade, but with possibly more pitting showing on the receiver. The rifling will have no wear to start out with. If you're handloading, TJT gave excellent advice. You have to set the overall length for your specific bullet and barrel. Another thing, accuracy will improve some with use. The barrel needs to be broken in, and the action seated into the stock.

[Phil McGrath]

HHmmm, you measuring two different brand bullets and expecting too get the same numbers at the ojive.... That's wrong, just wrong son... For now don't worry stick just with 3.30 COAL with everything from 147-175.

[lapriester]

Fact is, you'll never see enough of a difference from a standard Garand to notice accuracy changes by fretting about bullet jump. It's hard to tell a 1/4" improvement in a rifle that generally can't ever shoot better than 2-4 MOA on a very good day from a solid bench rest. Or even a gun vice for that matter. I have a 308 Garand with every NM modification known to modern man done on it and I feel blessed that it constantly shoots 1.5 MOA.