6BR and AR Comp load

[JFrank]

Unfortunately the bolt on my Bighorn doesn't have an ejector. It has a mechanical ejector on the action itself so can't use the ejector mark sign.

It still gets the harder bolt lift but I'm trying out lower loads just to be safe and the accuracy seems OK. I went to the range last Sunday and tried out 28.4 and 29.0 grains of AR Comp. Doesn't seem to be any decrease in accuracy at the lower load. 5 shot groups at 100 yards:

I let the RO shoot my rifle on my previous visit and he shot a 5 shot group in the 0's with it which was his best ever. I think he said his best group before that was in the .2s. I gave him that target to take with him. He was pretty happy so he made a couple of very nice wind flags and gave them to me on my Sunday visit. The ROs at the range I go to are really great. I never used flags before and I was trying to look at the flags and the target at the same time and it was pretty hard. I need to work on that. Kinda difficult when you're left eye dominant and shooting right handed.

Turn your target sideways and your vertical is gone
I raised my scope UP with tall mounts, not only am I more comfortable I can see the flags easier.
J

 

[Ranger188]

Bart told me to start at jammed, cause you have only one way to go from there.

 

[afret]

If you jam the bullet into the lands, does the bullet actually go that far into the lands or does it just get pushed into the brass?

 

[swadiver]

depends on neck tension

 

[FeMan]

Unfortunately the bolt on my Bighorn doesn't have an ejector. It has a mechanical ejector on the action itself so can't use the ejector mark sign.

FWIW, I also have a Big Horn TL3 which is chambered in Dasher. At high pressures, I find my Bighorn gives readily discernible marks from the ejector cut out in the bolt face. Not that you should keep going until you find them (because you shouldn't), but IME Bighorns do give large, easy to read rectangular ejector stamps in your brass when you get the pressures.

 

[afret]

FWIW, I also have a Big Horn TL3 which is chambered in Dasher. At high pressures, I find my Bighorn gives readily discernible marks from the ejector cut out in the bolt face. Not that you should keep going until you find them (because you shouldn't), but IME Bighorns do give large, easy to read rectangular ejector stamps in your brass when you get the pressures.

Good thing to look for. Thanks.

 

[zap]

Bart told me to start at jammed, cause you have only one way to go from there.

This makes very good sense !

 

[swadiver]

I am a big fan of the 80 gr Berger HPFB bullets. i shoot 'em in all my 6BRs with a twelve and faster twist. having tried a number of powders, i have always come back to N135. jamming them 15 thou with right around 30 grs of powder, one's and two's and an occasional zero group are common. (5 @ 100 yds) it's an awesome bullet.

however, thanks to the original poster of this thread, i was motivated to run down to my nearest Bass Pro and pick up a pound of AR-Comp to try. initial results, in my twelve twist Brux on a Savage Target Action are very promising, similar to the OP's results. 28.4 and 29.0 grs appear to be very good. definitely will be doing some further testing.

unlike the OP, i have had no hard bolt lifts and no pressure signs at all up to 29.2 grs. i am assuming AR-Comp is similar to N135's burn rate, maybe a wee bit faster. in that case, there may be a node higher up, closer to 30 grs that is also good. i have gone as high as 32.2 grs of N135 with the 80's in this barrel with no serious pressure signs, but a noticeable heavier bolt lift. since the 30 gr node shoots just as well or better than at 32.2, i don't normally load that high. freebore on this barrel is around .085". All Lapua brass, BR4 primers.

stay tuned

 

[afret]

I am a big fan of the 80 gr Berger HPFB bullets. i shoot 'em in all my 6BRs with a twelve and faster twist. having tried a number of powders, i have always come back to N135. jamming them 15 thou with right around 30 grs of powder, one's and two's and an occasional zero group are common. (5 @ 100 yds) it's an awesome bullet.

however, thanks to the original poster of this thread, i was motivated to run down to my nearest Bass Pro and pick up a pound of AR-Comp to try. initial results, in my twelve twist Brux on a Savage Target Action are very promising, similar to the OP's results. 28.4 and 29.0 grs appear to be very good. definitely will be doing some further testing.

unlike the OP, i have had no hard bolt lifts and no pressure signs at all up to 29.2 grs. i am assuming AR-Comp is similar to N135's burn rate, maybe a wee bit faster. in that case, there may be a node higher up, closer to 30 grs that is also good. i have gone as high as 32.2 grs of N135 with the 80's in this barrel with no serious pressure signs, but a noticeable heavier bolt lift. since the 30 gr node shoots just as well or better than at 32.2, i don't normally load that high. freebore on this barrel is around .085". All Lapua brass, BR4 primers.

stay tuned

I'm doing the reverse. LOL I'm trying out N135. I just got a couple of 8lb jug of the stuff. I tested with 28.3 and 28.4 grains yesterday at the range. I had loaded up more with 28.5, 28.6, 28.7, and 28.8 grains. I loaded up 25 rounds at each weight. I was getting hard bolt lift with 28.3 and 28.4 grains. It was pretty windy with a storm blowing in and the wind kept increasing as I was shooting. There was blowing snow all last night and the snow just stopped about an hour ago. And it's still windy now.

I had a couple 5 shot groups in the .1s with 28.3 and one with 28.4 grains. I think the wind affected a bunch of my other groups. It does shoot well with N135 but I can't figure out why I get the hard bolt lift at such low loads.

When I got back, I got the bullet puller out and took care of the 100 rounds with the higher loads. That was fun.

I loaded up 50 rounds with N135 from 26.8 to 28.0 grains and will be going to the range tomorrow just to see how the bolt lift is at those loads. The 80 grain Berger bullets are about 0.005 from the lands. The loaded neck diameters are 0.268. I use a FL bushing die with a 0.266 bushing and I follow that with a mandrel ( Sinclair turning mandrel). The barrel is an X-Caliber 12 twist. The chamber has a 0.271 neck and .094 FB. Brass is Lapua and primers are Federal 205M.

One thing I do notice is that the bolt lift seems fine on the first couple of shots. I wonder if the chamber heating up might have some effect. When I go to the range, I usually test with 50 rounds and I usually shoot all 50 in about 35 minutes or so with no cooling time. The range tends to be cold here though and has been in the 20-30 degree range. Tomorrow morning will be in the teens when I'm there. Oh, and I've been using a battery powered fan aimed at the barrel/scope to get rid of barrel heat mirage.

 

[urbanrifleman]

I am a big fan of the 80 gr Berger HPFB bullets. i shoot 'em in all my 6BRs with a twelve and faster twist. having tried a number of powders, i have always come back to N135. jamming them 15 thou with right around 30 grs of powder, one's and two's and an occasional zero group are common. (5 @ 100 yds) it's an awesome bullet.

however, thanks to the original poster of this thread, i was motivated to run down to my nearest Bass Pro and pick up a pound of AR-Comp to try. initial results, in my twelve twist Brux on a Savage Target Action are very promising, similar to the OP's results. 28.4 and 29.0 grs appear to be very good. definitely will be doing some further testing.

unlike the OP, i have had no hard bolt lifts and no pressure signs at all up to 29.2 grs. i am assuming AR-Comp is similar to N135's burn rate, maybe a wee bit faster. in that case, there may be a node higher up, closer to 30 grs that is also good. i have gone as high as 32.2 grs of N135 with the 80's in this barrel with no serious pressure signs, but a noticeable heavier bolt lift. since the 30 gr node shoots just as well or better than at 32.2, i don't normally load that high. freebore on this barrel is around .085". All Lapua brass, BR4 primers.

stay tuned

My fire forming load with 108s is 29.6.

With the 80s I have gone into the 32s. One of the best fire forming 6bra load with the Berger 80 was 32.5 at 3284 fps

I'm not sure what's up with his rifle. Ar comp is essentially the same as H4895. Actually it appears to be identical in charge to velocity ratio as h4895 in 6br/6bra/dasher.

But the lots are better.

 

[zap]

I picked up some AR comp to test out in my 8 twist and 12 twist Br's. Should be testing soon. Very encouraging info above.

 

[zap]

I was able to by 1/4# of AR Comp from a local store to test. Weather was nice at 5 pm yesterday, overcast and nearly no wind.
This powder is great, thats all I will say. Only 18 shots to get a load that produced a 5 shot group in the high ones.

I will try again to confirm with some consecutive 5 shot groups, but think it will be fine. Im thinking about tweaking my action screws also for further testing. (Savage target action)

 

[swadiver]

i have been doing quite a bit of testing with AR-Comp. i managed to get hold of an 8 pounder here local in FLA. a 12 twist 6BR Brux barrel, with 80gr Berger FB bullets (jammed .015") on a Savage Target action loves the stuff. both 29 grs and 29.6 grs shot very, very good with nod going to the 29 gr load. it also worked well with the 68 to 70 gr class of bullets on the 12 twist and a 13.5 twist 6BR, but I still preferred N135 overall for those weight range bullets. the OP had also tried 28.4 grs and was happy (i believe) with the results. i tried that load as well. it shot a very tiny group or two, but was inconsistent in my rifles.

definitely a good alternative to N135.

 

[Mulligan]

Went to the range this morning to shoot my 6BR with AR Comp to see what a bit of neck turning will do and put up two wind flags. The wind was 7-8 MPH and it's weird how the two flags can go in opposite directions. Tried to get the shot off when the flags were close to the same as the previous shots. The neck turning seemed to get rid of the hard blot lift problem which doesn't make sense since it's a no turn chamber. I had the bullet seated at the lands. Shot pretty well even with the breeze. I was going to do ten groups of 5 but I took my nephew and he had a problem with his 22BR which could only be fixed at home so only got 7 groups.

Wonder how AR Comp would work with a 6 PPC?

nice!
What bullet?
CW

 

[swadiver]

i am finding 29 grs of AR Comp with the Berger 80's to be a winning combination in two 12 twist and one 8 twist 6BRs.

However, i have the same barrel as the OP, i believe (12 tw X Caliber 6BR), chambered by X Caliber as a large shank Target action Savage Pre Fit. this one has too much vertical at the 29 gr charge weight, but has shown excellent promise around 29.6 or 29.8 grs. even as high as 30.5 gs shot well but not as good as the 29.6 area. i jam the Bergers .015". not sure what seating depth afret is using with these 80's. i have had no hard bolt lifts at all with 4x fired Lapua brass, not neck turned, even up at the 30.5 gr point.

looking at Afret's results here, i may have to try the 28.4 gr area as well.

also, as is well known, N135 with the 80's is another great combo. as advertised, usually around 30 grs of N135 is the ticket.

if you have AR-Comp or N135 and 80 Berger FB bullets, i think you can find out how well your 12 twist or faster 6BR can shoot.