Back in 1993 I had a Colt HBAR turned into a service rifle, leaving me with a spare 20" Colt 1/7 barrel on hand. I finally decided to turn the spare barrel into a rifle, as all my other rifles were 11.5" to 16", so why not have a 20" too?
As I slowly acquired the funds, I purchased a RRA lower receiver from
gunguyr, a CMT upper from
dennysguns, and a RRA lower parts kit from
Legal-Transfers. No hassles from any of the board sponsors. I traded a Colt bolt carrier for a Colt Delta free-float tube and bought a YHM gas block/front sight from Brownells. I finished it off with a spare Colt bolt carrier assembly, flash hider, and A2 buffer/stock assembly I already had on hand. Put on a Harris bipod and topped everything off with a Leupold Vari-XIII 1.5-5x on a SPR mount purchased from
MSTN. (I still need a 40L-SP rear sight--have to figure out what dealer to farm that purchase to.) The WI hometown moderator BulletcatchR was kind enough to lend me the receiver block and I already had a wrench, so I was off to the races.
I took it out to the range for the first time today. 58 degrees, 42% humidity, sunny skies, breeze variable at 6-10mph. I started off with a function test of 20 rounds Federal AE 55gr. No problems, although the group eyeballed over 3moa!
Well, it has been a long time since I've been active in Service Rifle, so I figured I was pretty rusty shooting off a bench. I wasn't sure whether to hope I was shooting badly, or whether it was a rifle problem--either one was unattractive
I built this thinking it might be a decent small-caliber deer rifle (no flames from the anti-.223-for-deer crowd, it's legal here and I understand the limitations of the cartridge). So after adjusting the sights for the Fed 55-gr ammo, I put 5 rounds of Winchester 64-gr PowerPoints through it:
OK, down to 2moa, and I'm starting to remember some of the principles of shooting off a bench...like squeezing the trigger and follow-through
. POI is about 1.75" off from the 55-gr FMJ load. I adjusted the sights, and got this:
1.5" 5-shot group, strung vertically, but right at 1.5" above point of aim. Nice windage, too! Amazing what a difference squeezing the trigger makes...
I decided to finish off the rest of the box of Winchester 64-gr ammo, and decided to test the QD "no loss of zero" feature of the SPR mount. So I took it off the rifle, then replaced it, followed by 7 rounds:
Another 1.5" group, centered and exactly where I wanted it...except for a called flier at 9 o'clock. I'm pretty happy with that.
Running the numbers, the Win 64gr (.234BC) @ ~2950fps 1.5" high @100yds w/sights 2.5" above bore gives me this trajectory:
YDS POI 0 -2.5
50 +.1
100 +1.5
150 +1.7
200 +.2
250 -3
300 -8.3
Since my hunting location doesn't have any possible shots over 175 yards, I think that should work well.
Finally, I finished off the test with all the remaining Federal Eagle ammo I had on hand, ~ 50 rounds, fired at 1/second, just to heat up the rifle. No function problems, and I got the HBAR smoking a little:
I still need to dump 200 rounds through it as fast as I can, to check the seating of the YHM gas block and give it a real wringing out, but so far I'm pleased.
Feedback? Comments?