Earlier I posted pics of my Hog Slayer/SUS VENATOR AR hand guard and mentioned POI problems with my Green Mountain 16" fluted, chrome lined 4150 steel Blackout bbl. Using the Barnes 110gr black tip 300 Blackout bullets which I've come to really like for hunting, no matter what the powder charge or primer, the 1st bullet would hit low. Tried it with and without multiple suppressors, different bolts, different magazines, different number of rounds in magazine, letting bolt go home with bolt catch, letting bolt go home by pulling charge handle all the was back and letting go, loading first round by placing it on top of mag, checking all screws, taking all apart and putting upper back together, firing fast so all was getting hot, firing SLOW (as in 1 shot per 5 or more minutes with fans cooling all in-between shots to ambient temperature so the bbl was always shot cold, clean bore/dirty bore, it made no difference, the 1st shot was out 90% of the time. Gaged the throat (a new bbl, it gaged as new). Also tried a group loading 1 round at a time...nice group, just all shots were low. No obvious defects seen in the bbl. Representative groups:
Getting desperate/perturbed/frustrated/whatever, prior to going home the other day, I fired 2 quick groups with one of my plinking loads using pulled 7.62x39 123gr fmj bullets. While the groups weren't small, only of soda can size, the 1st rounds were in the middle of the groups. Hmm...I decided to try some loads with the Nosler 125gr Ballistic Tip bullets. I'd used them for years (taking 7 hogs, 10 deer, and 3 coyotes) until the Barnes became readily available. It was like flipping a light switch. No more 1st round is out of the group in the 10 groups I fired today. I did find with the Noslers that with an cartridge OAL of 2.1" about 25% of the time I had a failure to feed with the round jammed against the feed ramp. With a 2.2" OAL I had zero failures to feed. I have loads with both OAL's on hand, as some of my other Blackouts have an OAL preference for either feeding or accuracy. You'll note the POI varied...As I was shooting groups and getting good results, I was also tweaking the POI to get it closer to sighted in. Representative groups:
4' from the chronograph, 19.0gr H110, Nosler 125gr BT, Wolf KVB223M primers, 2.2" OAL, LC formed brass, no crimp, no anneal, averaged 2198fps. A little faster than in some of my 16" bbls and a little slower than in some of my 16" bbls. Note: This is a hot load; start low and work up. If this powder charge was used at 2.1" OAL it would definitely be overpressure. Also the KVB223M primer is a harder primer for higher pressure loads.
It was suggested that I eject the 1st round chambered. Fire some more and eject the 2nd or 3rd round chambered and compare the bullet tips. Didn't do that, as I'd not brought any of the Barnes loads to my last two outings to test ammo...interesting idea, but I don't know it would solve the problem. Another idea was to shoot my first loaded round into the ground prior to walking to the hunting area. While that would work at my brother's farm, it might not be feasible for night hog hunting when you may have occasion to unload and reload when going to different fields or areas.
Getting desperate/perturbed/frustrated/whatever, prior to going home the other day, I fired 2 quick groups with one of my plinking loads using pulled 7.62x39 123gr fmj bullets. While the groups weren't small, only of soda can size, the 1st rounds were in the middle of the groups. Hmm...I decided to try some loads with the Nosler 125gr Ballistic Tip bullets. I'd used them for years (taking 7 hogs, 10 deer, and 3 coyotes) until the Barnes became readily available. It was like flipping a light switch. No more 1st round is out of the group in the 10 groups I fired today. I did find with the Noslers that with an cartridge OAL of 2.1" about 25% of the time I had a failure to feed with the round jammed against the feed ramp. With a 2.2" OAL I had zero failures to feed. I have loads with both OAL's on hand, as some of my other Blackouts have an OAL preference for either feeding or accuracy. You'll note the POI varied...As I was shooting groups and getting good results, I was also tweaking the POI to get it closer to sighted in. Representative groups:
4' from the chronograph, 19.0gr H110, Nosler 125gr BT, Wolf KVB223M primers, 2.2" OAL, LC formed brass, no crimp, no anneal, averaged 2198fps. A little faster than in some of my 16" bbls and a little slower than in some of my 16" bbls. Note: This is a hot load; start low and work up. If this powder charge was used at 2.1" OAL it would definitely be overpressure. Also the KVB223M primer is a harder primer for higher pressure loads.
It was suggested that I eject the 1st round chambered. Fire some more and eject the 2nd or 3rd round chambered and compare the bullet tips. Didn't do that, as I'd not brought any of the Barnes loads to my last two outings to test ammo...interesting idea, but I don't know it would solve the problem. Another idea was to shoot my first loaded round into the ground prior to walking to the hunting area. While that would work at my brother's farm, it might not be feasible for night hog hunting when you may have occasion to unload and reload when going to different fields or areas.