M1A range report

[7br]

I purchased a used Springfield M1A. Today was function testing. I was shooting out of the bed of my pickup ay 50 yards. Temperature was about 40 degrees and had a bit of sleet spitting. It was not ideal shooting conditions. I started with the Lyman 311299. 2 rounds at 27.5 gr pf H4895, then 3 rounds going up in .5 gr increments to 31 grains. All rounds had dacron fillers. The first 27.5 round ejected, but the second round did not fully go into battery and did not fire. All other rounds functioned fine. Groups ranged from 4in down to 1 in with better groups above 30 gr. Second go was with lyman 311291 starting with 2 rounds with 25 gr of H4895 and then going up .in .5 gr increments for 3 rounds to 29 gr. All loads had dacron fillers. All rounds fully cycled the action. Groups wete 3 inches down to 1 1/2 inch. I am not putting to much stock on group size at this point. I am trying to wrap my head around the relationship between bullet weight, powder charge, pressure and gas volume and how it relates to proper cycling
IE, should I need more powder to cycle the actipn for a heavier bullet, should stay the same, or should I need less.

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[Ford SD]

Have you read Bruce B Write up on the M1a

He did lots of work so we do not have to

Depending on barrel twist M1a have 1/10 or 1/11 Depending on Model will effect accuracy/velocity

Others have added to the stickie

[country gent]

Actually the military barrels are 1-10 or 1-12. Springfield armory used a lot of 1-10s. Another is there were several different throat lengths leads used over the years

[7br]

I have read it and it was a great help, but I figure it is still going to take some work to find the sweet spot.

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