Saturday I made a trip to the range with the M25 and the 5R, and today was my 15th wedding anniversary.
The reloading problem is taken care of, as is the scope mounting issue, but my first handloads for the M25 weren’t all that stellar. I also tried out some new handloads for the .38 Super. Berry’s 124 grain hollowpoints don’t work very well with the feedramp on the Witness. 1,300fps though, and nice, tight little groups when it did feed.
I did Vicious Circle Thursday night, and got all gun-geeky afterward with Aepilotjim discussing handloads. I’m a little concerned that the loads I’m testing are a bit too stressful for the M25. I started off with 45.5 grains of Reloder 15 in a Lake City “LR” case – the case used for the M118LR round – under the Lapua Scenar 155 grain BTHP, touched off by a CCI #34 military primer. It’s a very slightly compressed load, and if my chronograph is to be believed it yielded an average velocity of 2890fps and a standard deviation of 16.4 out of the M25, and 2920fps and a standard deviation of 10.8 out of the 5R.
My standard load for the 5R is 46.4 grains of RL-15, same bullet, Lapua case and CCI benchrest primers. THAT load over the same chronograph, produces 2790fps out of the 5R with a Sd of less than 10fps. The difference being that the latter load out of the 5R typically groups well under 1MOA at 200 yards. (I busted some rocks out at a laser-measured 650 yards just for fun with that load.) The Lake City-cased load grouped about 1.75MOA. Out of the M25, a bit over 2MOA.
Part of the performance difference, both velocity and accuracy, may be reduced case volume due to the use of a small-base sizing die and military brass (the M118LR brass is not supposed to be as thick as standard Lake City 7.62 brass, but still). The smaller case dimensions after sizing may also adversely affect bore concentricity out of the 5R, too. The military “magnum” primer probably has some effect as well. However, Jim pointed out that Reloder 15 is a much slower powder than is normally recommended for the Garand/M-14 gas piston design. I did a little research previously, and the standard powder for the M118LR load is Reloder 15, but in the Sandbox they discovered that high temperatures were causing the standard load to be too hot for the M-14 based rifles, and this resulted in bent op-rods. The correction was to reduce the powder charge. The M118LR uses a 175 grain Sierra Matchking bullet. I’m using a 155 grain bullet, and pushing it a LOT faster. Hmmm….
The plan is to try to find one load that both rifles like. That might not be possible, I acknowledge, but it’s my intention to try.