I have a brand new Springfield M1A that I just started loading for. I loaded some IMI brass with the appropriate load and went to the range and got super results. I came home and only neck sized them. When I went back out to the range I found that they would not seat completely into the chamber. I in fact let the bolt fly on the first one which got the round stuck and had to about force the charging handle back to get it to extract. I know on my AR I only neck size and all works fine. I did full length size the brass when i got home and they chambered fine. I guess my question is on the M1A you must always full length size. You would think once it fire formed to your chamber you would be good. Has anybody ran into this. I hate full length resizing but it looks like it is a must for this rifle.
Springfield M1A full lenght resizing
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Sport45
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IMO, you've been lucky in only neck sizing for your AR. I have to full length size for my AR and do the same for my M1.
Mark whiz
Member
Forget neck-sizing M1A brass - they are way too rough on brass to try it. The Gas ejection system basically rips the brass out of the chamber before it can fire form, so every spent casing is gonna be a little different dimension-wise.
jpwilly
Member
You should Full Length size virtually all reloads for use in Semi Auto's even when it's the same one shooting the same brass. One other issue aside from getting the case stuck before the rifle goes into battery...the free floating firing pin that could cause a SLAM FIRE out of battery to boot!!
ReloaderFred
Member
I have two M1A's, and they both require full length sizing. As mentioned, the M14 system is very fast and hard on brass. Also the advice jpwilly gave you about the danger of a slam fire with oversize brass is good advice.
Hope this helps.
Fred
Hope this helps.
Fred
FROGO207
Member
I agree with the last two posts that you DO need to full length resize your brass on any semiauto as it will not chamber well otherwise. Slam fires are also a real danger. It is a pain to FL size but it will make the firearm more safe and dependable.
Always full length resize brass to be used in gas guns. It is a safety measure for semi autos with free floating firing pins. The M1a and Garand are particular examples of rifles with free floating firing pins. And ones that have had out of battery slamfires.
I recommend that you buy a case gage and set up your sizing die with that case gage.
This is a Wilson case gage.
I also recommend using a small base sizing die. If you use a small base die, spray on lubes won’t provide enough lubrication. You will need to use RCBS water soluble or Imperial sizing wax as a lube.
The RCBS small base X Die is popular with the guys on M14.com. But any small base die will work fine. You just have to set them up with a case gage or you will push the shoulder back too much.
One thing about the Wilson gage. It measures length only. It does not measure “fatness”. This has its advantages as you can measure the length of a fired case and determine whether your rifle is within headspace.
This picture has two unsized cases. One in the Wilson gage, and one in a gage cut with a chamber finishing reamer. Obviously the fired cases need sizing or they will be an interference fit.
One other thing. Primers. Always seat primers by hand and verify that they are below the case head. Reaming pockets to depth is a good extra step. Use the "least sensitive" primers you can find. I recommend CCI#34's. I have been told that Rem primers are very insensitive. Based on my own useage, regular CCI LR have thick cups. Never use Federal primers. Federal primers are the most slamfiring primer ever in a M1 or M1a.
I recommend that you buy a case gage and set up your sizing die with that case gage.
This is a Wilson case gage.
I also recommend using a small base sizing die. If you use a small base die, spray on lubes won’t provide enough lubrication. You will need to use RCBS water soluble or Imperial sizing wax as a lube.
The RCBS small base X Die is popular with the guys on M14.com. But any small base die will work fine. You just have to set them up with a case gage or you will push the shoulder back too much.
One thing about the Wilson gage. It measures length only. It does not measure “fatness”. This has its advantages as you can measure the length of a fired case and determine whether your rifle is within headspace.
This picture has two unsized cases. One in the Wilson gage, and one in a gage cut with a chamber finishing reamer. Obviously the fired cases need sizing or they will be an interference fit.
One other thing. Primers. Always seat primers by hand and verify that they are below the case head. Reaming pockets to depth is a good extra step. Use the "least sensitive" primers you can find. I recommend CCI#34's. I have been told that Rem primers are very insensitive. Based on my own useage, regular CCI LR have thick cups. Never use Federal primers. Federal primers are the most slamfiring primer ever in a M1 or M1a.
loadedround
Member
Ping: I also have an M1A and it is a NM rifle. If I necked sized my reloads, i would still be hammering out that empty case from by chamber assuming I could have chambered it. I full length resize all my cases including new brass in a Redding FL sizing die. I did buy a small base sizing die, but to date have not needed it.l I've been reloading once fired Federal Match brass. I have a large quantity of once fired LC Match brass and expect to have to use the SB sizer on these. Good shooting. 
Here is a good link about loading for the M14/M1A:
http://www.zediker.com/downloads/m14.html
Read this and you will never even *think* about failing to full-length resize again.
Tim
http://www.zediker.com/downloads/m14.html
Read this and you will never even *think* about failing to full-length resize again.
Tim
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