You want to full length resize your brass with .004" set back at the shoulder on gas guns.

Try a powder like RL-15, Varget, 4895, or 4064, nothing slower. Trim case lengths to minumum as noted above, and try a different primer, again as noted above. Also, check the weight of your brass. If the Lapua is a new brass for you, it may way more than WW or Rem. That would give a smaller capacity and higher pressures.

Pull the gas system apart and clean and lube it with a dry teflon lube (Teff Dry by Bore Tech, or Rem Dri, by Remington).

Have a gunsmith check your bolt lugs for set back.

Get a box of factory match ammo. compare velocities to your handloads. Alternate rounds of factory with handloads in the clip. See if you can feel any difference.

Do a web search for an article about port pressure. 15 - 20 years ago there were articles in both Handloader and The American Rifleman.



I would recommend getting the new Hornady manual. It has a section of loads tailored for the M-1A and M-1 Garand rifles. Since you are shooting 308 you would want to look at the section on the 7.62x51 in the M1-A.



These are great guns, and very shootable. They are pretty picky about having the correct port pressure in the gas system. Because the brass cycles through greater size changes during the reload/shoot cycle I pitch it after 4 reloads at a maximum.



Glen Zediker's book about competition reloading has some great chapters on this subject.



You did something very smart. As soon as something felt amiss, you stopped what you were doing and started to ask around.



Good luck,

JCN

I went out after some adjustments and had a primer back out a little on me. That has to mean that the pressure must be getting fairly high. I have some that are loaded to touch the rifling, but too scared to use em now. I checked the case lengths, nothing out of the ordinary. I just feel that the fit in the chamber is rather tight, or on the long side. I just can't put my finger on why when everything checks out on measurements.

James,



You mention that you checked the Hornady handbook for a reference after loading some shells. I have the fifth edition Hordady book and it does not list IMR 4320 for the

7.62 x 51 NATO round. Since you are shooting a M1 I would

assume you would like to load for it and not a model 70.

You also mention that the cartridge seems long. Make sure

when loading for the M1 to full length resize your brass, which you may be doing but I did not see a mention of it.

Primers backing out is not necessarily a problem of over pressure. You primer pocket may be too large and I have found in the past that some primers such as CCI just don't stick as well. The Hornady handbook calls for WLR primers and they are my preference as well. As far as over all length of the round the Hornady handbook calls for that round to be at 2.800". You may want to try this. I load for A M1-A national rifle and use AA 2520 that is listed in the Hornady handbook. It is a little faster burning and this will reduce recoil. I am using the same round with good results in A HK-91 match rifle. Hope this helps!

Good Shooting

Gary

Hey Gents,

I am reloading .308 : Lapua Brass, 168gr Hornady A-Max,
IMR 4320 Powder @ 40.2 grains. According to the Hornady reloading manual it should acheive around 2400, ( I also used the speer, and RCBS manuals as double checks).

My question is this... I am reloading these for my M-1D. Everything on it is built to achieve the highest in accuracy. I have put thousands of rounds through it and I have a fairly good idea of how much recoil I should get if I put in everything from 168 grain Fed Match to south african surplus. I just went out today and put 8 rounds of my "new" reloaded ammo through it today. The recoil felt like something out of the 180grain hunting ammo I have used before. I seat the bullet at the same depth as the Hornady A-max commercial stuff, but when I seat my rounds in my rifle, it is almost as if the cases are too long. Is any of this normal? I have only started reloading, so any ideas are appreciated.

James

To expand a little on what elkhntr said, if your case necks are getting too long they can catch in the throat of the chamber and hold the bullets in too tightly. When the bullets can't get out of the cases easily, pressures go up in a hurry.

This may be obvious, but are you trimming your brass and checking cartridge overall length?

I think you may be getting too high of a port pressure for the gas system on your gun. The burning rate on your 4320 may be too slow.
JCN