16 March 2009
Chrono fun part deux!
I'm on furlough from the dayjob(tm) this week. So what better time than to take the family to the range! Weekends are pretty much SRO this time of year but during the week we have our pick of benches.
My mission for the trip was to chrono several centerfire rifles & loads. It took longer than expected because as we went up through the calibers, the Chrony had to be moved back to save it from the muzzle blast. Five feet was enough for the .22 and .223. But one shot of from the Garand sent the light shields flying. At 12 feet it was far enough to be safe from the muzzle blast, but my aging eyes were barely adequate to read the numbers at that distance. Fortunately we brought along a pair of 9YO old eyes.
The data showed some interesting comparisons. The first two columns compare MilSurp 30-06. First column fired from an M1 Garand and the second from a 1903 Springfield. Same bullet from two different rifles and the semi-auto Garand only sacrificed 6 fps to the Springfield. I expected the bolt action would perform better. At least the impact to my shoulder suggested it would.
The second pair of columns show my reloads in the same caliber and rifles. Looks like I can pep those up a bit.
The third pair shows two different reloads in .223 Rem. I started using the same IMR4895 as used for the 30-06 but there is a note in the Dillon manual recommending against stick powder in calibers less than .30. So I tried some AA2460. As you can see the results are just about even. But the data also shows (even though the graph does not) the AA2460 is more consistent with a standard deviation almost half of the IMR load (33fps for the AA, 54fps for the IMR). Hmmm, cheaper, faster, more consistent. It's just better all around!
The last column shows an 8mm Turkish Mauser firing 1937 MilSurp. The whole package of rifle + 700 rounds sold for under $80 a couple years ago. I don't shoot it much as it's quite the shoulder-crusher. As expected it was the fastest of the group. Also most consistent with a StdDev under 16 fps.
Meanwhile the SCQueen and SCSon brought along a collection of .22s and had fun blasting through a part of a Big box of Federal.
The SCQueen also tried the AR-15 for the first time and found out what a delight it is too shoot. I started her off with just a couple, but when asked if she wanted more, she was only too happy to oblige.
What a beautiful day for a furlough! (But payday-friday is gonna suck).