Let me start with two disclaimers
AR PISTOLS ARE HARD TO BENCHREST
I have yet to see any real positive accuracy results from 300 black in short barrels or subsonic WITHOUT reloading. I am not interested in reloading any rifle yet. Maybe later.
AR PISTOLS ARE HARD TO BENCHREST
My set up is a linear comp, YHM free float tube, standard trigger (ugh.... I know), Car buffer and spring. Anderson upper and PSA BCG, and for tests a 4-16 power scope that has proven good for range use. The scope hung over the end of the barrel, so I backed it up a little farther than comfy to keep blast away from the front lens. Shooting this thing is not easy on the neck or shoulders from a bench. Standing is just fine with a red dot...just not with the huge scope.
Fit and finish are fine. The balance is great, except that the sig brace is too heavy. I will put on an MFT or DD once I get an ATF permission slip. THIS THING IS LIGHT AND NIMBLE. EVERY shot has been stabilized and round holes on paper. All supersonic rounds have cycled flawlessly, and I have learned that MOST subs will cycle if you change the standard hammer spring out for a JP red hammer spring.
With a standard hammer springs almost nothing SUBSONIC ever cycled, but 3/4 would at least eject and close back on an empty chamber or attempt to load the next round. Some would just roll out of the chamber onto the table.
I demoed my can for 4 shots of sub and 4 shots of super (HOG HAMMER EXPLOSIVE CRAP). Super cycled emphatically and spit fire and brimstone out the ejection port once. Subs felt like I had just held a Glock 34 up, smooth and soft with perfect 4:00 ejection, but were not nearly as quiet as I had hoped.
. YHM ULT. Maybe the barrel is too short for hushness with such a small volume can. Even with the can attached the balance was towards the rear with the Sig brace. MUST GET STAMP
.
All supersonic cases ejected in a nice 24" circle at 5:00 about 8 feet away....except HOG HAMMER....see below.
GROUPS - format is (best 4 / all 5) center to center distances extreme spread. Anything over 2" just gets a tape measure instead of caliper. I normally just do the center to center of the farthest 2 shots, but my methodology had to change since 300 black and 6.8. My 556's have always posted entire 5 shot groupings on 2" pasties.
Day 1 - A cotton field on a shooting bench in stiff 5-10 mph winds. I had to do some work to get a target stand to hold still in the wind. 100 paces. I'd guess between 95-105 yards.
Remington 120gr OTFB - not bad.
5 shots to zero at 100, then
1.60 / 1.78
1.51 / 1.92
.85 / 1.54
Remington 125gr OTM
Bore snake then directly to grouping as first 3 shots nearly touched.
2.55 / 4.2
1.81 / 2.81
1.97 / 1.98
1.30 / 2.30
Remington HOG HAMMER 130gr TSX
BOOOOOOOOOOM.....AAAGGGGHHHH.. .. No blood...I'm ok.......Case looks normal...ears ringing despite hearing protection...Case went to 3:00 12 feet away....THIS STUFF IS HOT. I does not even seem like the same caliber. Kicked the whole gun up in the air from the table. I wouldn't want this stuff hitting me for sure. All rounds made nice round and crisp holes.
bore snake, then after 1st shot I adjusted the scope to get POA closer to POI. Turns out this was futile.
4.2 / 4.8
1.73 / 2.21
2.4 / 3.7
done. put the last 4 rounds back in the box. I had seen enough. Now this stuff is pure copper so maybe if I had done a full cleaning first, then let the bore adapt to it the results could have been better, but I am really only interested in subsonic use. sooo next
Remington 220gr OTM
I cranked the scope up several MOA. Bore snake then 1 shot to adjust zero.
2.40 / 3.19
4.2 / 5.7
3.6 / 4.7
put the other 4 back in the box in complete disgust. 2 or 3 did cycle with the standard hammer spring. The rest just rolled out on the table or did not eject. some empties jammed in the receiver without a live round being caught by the bolt.
Hornady 208 gr AMAX
bore snake. first shot was not on paper. Fired again and my target disappeared like Scotty had beamed it up. I go up to find the bullet hit low on the metal stand and COMPLETELY destroyed it. It was at least 5 foot back and the IPSC target that was holding the back of the stand stable was gruesomely decapitated. My day was over. Poor prop man
ROUND 2. Local range, 100 yards, 0-5 mph winds perpendicular to range
I had swapped in the red JP hammer spring on a hunch.
Hornady 208 gr AMAX
Took several rounds to finally get on paper at 100 yards. Only had 11 rounds left to play with.
1.70 / 3.0
2.3 / 3.0
Hornady 110gr V-MAX
boresnake, then a few shots to adjust zero for supersonics again
1.90 / 1.92
1.25 / 2.5
1.61 / 2.88
SUMMARY, WALMART REMINGTON 120gr OTFB is economical and accurate enough (1.75 MOA ish) for supers. I have not found any good subs for this barrel. An H2 buffer would probably be better for supers, but the Car buffer did just fine except with the HOG HAMMERS.
PLEASE give me recommendations for a cheap bulk source for good subsonic ammo.