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Posted: 9/2/2009 11:17:21 AM EDT
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I need to feed a new AR. The AR is a Double Star lower, BCM mid length upper, topped with a Millet DMS.
My first load was Hornady 55 gr FMJBT WC, 25 gr Varget, 2.225 COL, Rem Primers. Brass is mixed, trimmed to 1.750. I loaded 10 of these, then 10 ea of 25.5 gr and 26 gr of Varget. A range test showed the groups opening up as the charge got larger. Loaded up 10 more rounds with 24.5 gr Varget and got the best group yet. http://i700.photobucket.com/albums/ww7/cactus_jack/24_5varget.jpg The shot to the far left was a cold bore shot. Do I need to warm up the barrel with a few rounds first or is that a myth? What is the best group I can expect out of my rifle with a 55 gr FMJBT? I have read 2 moa with a FMJ but think I can do better than that with some practice. I only have 200 rounds thru the AR and had not shot a rifle in years. I am hesitant to reduce the load anymore. The 24.5 gr felt like a powder puff load. The ejected shells didn't quite roll off the shooting bench, but were landing 5-8' away at 2 o'clock. Is this load GTG or would you tinker with it some more? I have no delusions of this being a sub moa set up. If that was what I was after, I would get a better bullet, barrel, scope, etc. I just want to find the best load for the cheapest projectile, load and shoot a bunch of them. Thanks, Fred |
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Your gun is most likely the limit of accuracy, particularly if the barrel is not floated; its potential accuracy is a guess, they're all over the place. It might shoot an inch, and it's obvious that it's not shooting 6 inch groups, so there's hope. [I had a rifle for a while that wouldn't shoot worth a crap, the best it would do was 3 or 3 inches with a reliable handload, and girnormous groups with factory ammo.]
Cold bore-clean bore and cold bore-fouled bore shots will generally land outside the group of most rifles. If you're going to hunt with the rifle, I recommend a zero with a cold bore-fouled bore as that is the most likely condition during follow up shots. If you shot only one group with each charge, that's insufficient, although 10 shots is better than some of the three shot groups that are used to decide on a load. I think you should go back to a 25 grain charge, then work your way up to about 27 or 27.5 grains (the case will be full and the charge compressed) in 0.3 or 0.4 grain increments. I wouldn't shoot 10 round groups as it uses up components, but that's okay if it suits you. I bet you'll find another load at a higher charge that will tighten up. Make up a few fouler rounds to shoot before shooting the group. Shoot the foulers into a different bullseye. Try a 52 grain Sierra MatchKing, preferably with 27.0 grains of RE-15, to find out how well your rifle will shoot. |
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Great replies everyone - Thanks!
It's interesting that there may be a sweet spot above the 26 gr load. The groups got consistently worse so I reduced the charge below my starting point and got better groups. I'll try the upper range and see what happens. Crunching the Varget into the case will be a bit unnerving. I'll hand select some of the best brass for that. As for heavier bullets, that is is another project. Right now I am looking for an accurate 55 FMJ plinking round. If I can get it to 1.5 moa I'll be happy. Fred |
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Quoted:
Of you go with 75gr hornady get vmax not amax the coal of the amax is too long to feed in an ar and has to be fed one at a time. I like the 68gr bthp match from hornady in my 20" 1:7. +1 on varget First off there is no 75gr Vmax, the heaviest is 22 cal is 60gr. With that said, the most accurate 22 Cal 55gr FMJ is the Hornday, but harder then Hen's Teeth to find right now. Otherwise unless you get some Speer 62gr FMJ there are no great opportuntities for great accuracy with FMJ bullets in 223. Both the 75 and 80gr Amax are VLD type of bullets meant for single shot use. If you are looking for large qty of plinking ammo...skip Varget hard to measure vs say using H335 or TAC. TAC with mid to heavy wt bullets has excellent accuracy potential. If you are looking for best accuracy.....get a Nosler or Sierra 69gr OTM and varget in same headstamp cases using Varget work up from 24.5 to 25.5 gr and I bet you going to find the best accuracy potential of your upper. |
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Quoted:
Of you go with 75gr hornady get vmax not amax the coal of the amax is too long to feed in an ar and has to be fed one at a time. I like the 68gr bthp match from hornady in my 20" 1:7. +1 on varget My S&W stainless 20" barrel 1:7 loves 50 - 60 grain bullets........5 shots quarter sized at 100 yds. (24 grs TAC) with 52 gr bullets. Maybe at 300 yds plus the 68-77 gr bullets would group better than the lighter stuff...... but at 100-200 yds mine likes the lighter bullets. I have a 1:8 DCM bushmaster that likes the 65 gr bullets best................just try different bullets weights in your barrel. |
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Quoted:
Your gun is most likely the limit of accuracy, particularly if the barrel is not floated; its potential accuracy is a guess, they're all over the place. It might shoot an inch, and it's obvious that it's not shooting 6 inch groups, so there's hope. [I had a rifle for a while that wouldn't shoot worth a crap, the best it would do was 3 or 3 inches with a reliable handload, and girnormous groups with factory ammo.] Cold bore-clean bore and cold bore-fouled bore shots will generally land outside the group of most rifles. If you're going to hunt with the rifle, I recommend a zero with a cold bore-fouled bore as that is the most likely condition during follow up shots. If you shot only one group with each charge, that's insufficient, although 10 shots is better than some of the three shot groups that are used to decide on a load. I think you should go back to a 25 grain charge, then work your way up to about 27 or 27.5 grains (the case will be full and the charge compressed) in 0.3 or 0.4 grain increments. I wouldn't shoot 10 round groups as it uses up components, but that's okay if it suits you. I bet you'll find another load at a higher charge that will tighten up. Make up a few fouler rounds to shoot before shooting the group. Shoot the foulers into a different bullseye. Try a 52 grain Sierra MatchKing, preferably with 27.0 grains of RE-15, to find out how well your rifle will shoot. 
That's a good shooting load, and not my best day at the range. |
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