Originally posted by Greg Skinner
View Post
"Max" load for AR Comp and 123s
Collapse
X
-
I'm 51 years old. I've been divorced for 10 years. I tried it, it didn't work, it's not for me. The last 2 tried to reel me in. That was a bad idea. Today I tried AR Comp. I might be in love!
To preface, I thought about not heading to the range today as I had planned. I'm a bit overtired and knew I wouldn't do my best shooting - just that gut feeling that your not going to bring your A game and will probably be lucky to have a C game. I headed out anyways with a thought at beating the high winds we've been having. That didn't happen as they were 10-15 mph with gusts to 25, generally from 10 to 11 o'clock. I strapped on the Magnetto and got to "work" with a ladder of AR Comp, 123 gr Scenars seated at 2.24, GM205Ms and virgin Lapua brass. I'm sure the wind had an impact on group sizes, the Magnetto gives a good idea of what a load will do (but it definitely opens them up a bit as it does experience minor mounting shifts) and I think I am just off the lands with the Scenars at 2.24 (I'm going to back off to 2.235 for the next round) From 27.0 - 28.0 grains, all groups were around MOA or better at 100 yards with 27.8 grains with 4 of 5 (which were shots 2-5) at 1/2"
Velocity and velocity variance out of my 22er (5 shots per charge)
Charge/ Ave / SD / ES
26.8 / 2482 / 7 / 20
27.0 / 2504 / 7 / 18
27.2 / 2513 / 9 / 26 (ES was 12 without a flyer from both group and velocity)
27.4 / 2533 / 2 / 6
27.6 / 2549 / 4 / 10
27.8 / 2565 / 4 / 11 (accuracy node in this area?)
28.0 / 2569 / 6 / 16
28.2 / 2580 / 4 / 12
But what I liked the most was how cool burning the powder is. At lighter charges, the brass was barely warm. At 28.2 it wasn't nearly as hot as some of my pet loads. Normally when I do load development I'll let a barrel cool after 3 rungs of 5. During my last outing with the JP (ladders with CFE and XBR) I did 4 rungs of 5 between breaks (I have the thermal dissipator - worth every penny). This morning I ran through 44 rounds with the 123 Scenars, only stopping to jot down my Magnetto results between rungs. At no point did my barrel even get close to the point where I would (in most other instances) put the rifle on the rack and shoot another while I let it cool. I had one faint ejector mark at 28.0 and 2 at 28.2. Could mean that it would need to be gassed down at those charges. Nary a sign of primer flattening at all levels, and the GM205Ms are relatively thin.
If there's a downside, it's that these are mostly compressed loads with the higher charges being rather compressed - so much so that you can feel the difference with the ram as you up the charge. And so much so that I needed to screw down my Forster die every time the charge was increased.
I did the same ladder with the 129ABLRs seated at 2.27. Experience with velocity variance was the same going from 26.8 grains at 2450 to 28.0 gr at 2511, with single digit SDs and ESs <20. Accuracy was around MOA with some a little more, some a little less. The best was 26.8 at 2450 at around 3/4". I'm going to see how long I can load the remaining 20 or so that I have before getting too excited. These are compressed to very compressed loads, but the only pressure sign up to 27.8 was an occasional slightly flattened primer, which I'm sure would go away if I used the harder GM205MARs. Again, a few faint ejector marks at 28 and 28.2.
All in all, on a day where I can actually shoot, I think there's a node with the 123 Scenars that will give me 1/2 MOA, 2550 fps+ AND an barrel that doesn't get much more than warm. I'm also really looking forward to trying AR Comp in my 308 RPR with 175s and in my 16" POF P308 which sees its share of 20 rd mag dumps. I can see why they call it AR Comp - the cool burning should keep a barrel from getting to hot and accuracy straying when it gets hot.Last edited by StoneHendge; 06-13-2017, 11:49 PM.Let's go Brandon!
Comment
-
-
This is some great data, sounds like you have a load that could really work. Pushing that 123 Scenar to 2550+fps will be a very nice long range load. I love AR Comp, I think its the best powder for the Grendel with 123 grain bullets be it Amax, Scenar, SMK, etc. The SDs you were describing are common for the powder and none of the loads I tested have run hot at all which should mean more life out of my brass.
Comment
-
-
Originally posted by Kilco View PostIs the velocity on par with 8208 XBR? Better?
1911man - I was thinking so much about a longer barrel life and more shots per range session that I didn't even think of brass life!Let's go Brandon!
Comment
-
-
Originally posted by Kilco View PostIs the velocity on par with 8208 XBR? Better?
Comment
-
-
I'm at a loss here. Virgin Lapua, GM205M, 123 scenar and 27.8 AR Comp. No Magnetto on barrel. Shots were in order of left to right. Probably about 10-15 seconds between shot. First 2 made me happy....
image.jpeg
Took a few minutes break. 10-15 seconds again - except for the high one in the middle. After the first four I took a minute or so break.
image.jpeg
Temp sensitivity? When I first started loading 308, I tried BL-C2 and IMR 4895 before I knew what temp sensitivity was. With those my strings were more vertical. I've shied away from anything with the reputation since
Edit: Note the pics are on their side on my iPad. The strings went left to right.Let's go Brandon!
Comment
-
-
Originally posted by Kilco View PostLooks like how my rifle groups CFE223... so frustrating.. you still have a little room to work up though, right?
And if anyone stumbles a cross this, how in the name of every diety that's ever been worshiped on this planet and any planet in the universe can a double action revolver double tap? We're not talking a 38 either - we're talking about a 3 year old 7.5" Super Redhawk in 44 mag. With some pretty warm 300 grainers. Going boom-boom with one pull of the trigger. Select fire rate. Barrel was pointing about 80 degrees up after the second. I had to check my underwear. Luckily it was at a very remote range and the closest shooters were 50 yds away.Last edited by StoneHendge; 06-17-2017, 02:04 AM.Let's go Brandon!
Comment
-
-
Originally posted by StoneHendge View PostGroups spread at higher charges. I'm going to work up 10 more and do one set with minute breaks and the other set at a the shoot / set / shoot pace just to confirm I'm not crazy. I'm going to revisit 30.8 CFE which gave me 5/8" (shots 2-5 were 3/8") and 2550ish with single digit sd, but I'm expecting dissapointment. 31.0 and 31.2 strung on me and I think I did the 30.8 after letting the barrel cool. If so, I'll probably be back with XBR with different primers
And if anyone stumbles a cross this, how in the name of every diety that's ever been worshiped on this planet and any planet in the universe can a double action revolver double tap? We're not talking a 38 either - we're talking about a 3 year old 7.5" Super Redhawk in 44 mag. With some pretty warm 300 grainers. Going boom-boom with one pull of the trigger. Select fire rate. Barrel was pointing about 80 degrees up after the second. I had to check my underwear. Luckily it was at a very remote range and the closest shooters were 50 yds away.
Two groups is not enough. Since they strung horizontal as you said (the picture was posted with the wrong orientation), I see very little vertical stringing which to me is a good sign. Most of the time that type of horizontal stringing with an AR shot from a rest is due to position and shooter error. I think you took way too long to shoot five shots. Try a standard sustained fire cadence and if you have set up a solid position, I bet you will see that your load is fine.
As for the Redhawk, you pulled the trigger twice.
LR55
Comment
-
-
Originally posted by LR1955 View PostSH:
Two groups is not enough. Since they strung horizontal as you said (the picture was posted with the wrong orientation), I see very little vertical stringing which to me is a good sign. Most of the time that type of horizontal stringing with an AR shot from a rest is due to position and shooter error. I think you took way too long to shoot five shots. Try a standard sustained fire cadence and if you have set up a solid position, I bet you will see that your load is fine.
As for the Redhawk, you pulled the trigger twice.
LR55
One thing I know I tend to do is push or pull a shot from where they are grouping towards the bullseye. Maybe I was progressively pushing these. Thanks - I'll give it another try - zeroing on the bullseye after my first 3
I was shooting the super redhawk single action off a bag at a gong at 50 yards. The double action trigger pull has got to be in the range of 12-15 lbs - no way I pulled it twice - I don't think Jerry Miculek could pull it that fast. I woke up thinking that it had to have been a slight hang fire and I had miscounted rounds firedLast edited by StoneHendge; 06-17-2017, 03:37 PM.Let's go Brandon!
Comment
-
-
I did a ladder with 123 SSTs and 123 NCCs and found 27.3 and 27.6gr AR Comp were the tightest shooting out of my Wilson 20" fluted. About 1.25 MOA with flier; .5-.75MOA with single fliers removed. I have a bunch more loaded up for further testing to see if the fliers were me (most likely). Sorry, no chrono data at this time.
Interesting note - I shot better using a bipod than a Caldwell rock Jr front rest on my Grendel and .223 Heavy-barreled AR. Small rear squeeze bag on each. I though AR's were supposed to be picky with bipods but it worked out well this time. Shooting off a smooth bench with no way to "load" the bipod. As with anything else, I think consistency is key.
Comment
-
-
Originally posted by Chrazy-Chris View PostI did a ladder with 123 SSTs and 123 NCCs and found 27.3 and 27.6gr AR Comp were the tightest shooting out of my Wilson 20" fluted. About 1.25 MOA with flier; .5-.75MOA with single fliers removed. I have a bunch more loaded up for further testing to see if the fliers were me (most likely). Sorry, no chrono data at this time.
Interesting note - I shot better using a bipod than a Caldwell rock Jr front rest on my Grendel and .223 Heavy-barreled AR. Small rear squeeze bag on each. I though AR's were supposed to be picky with bipods but it worked out well this time. Shooting off a smooth bench with no way to "load" the bipod. As with anything else, I think consistency is key.
I started using Norma 202 for 308 a couple of years ago in the powder drought. When I bought my lb of AR Comp, It wasn't too hard to figure out who made it for Alliant. I dusted off the Norma 202 to try in 22 Nosler earlier in the week. I trickle onto a balance beam for precision loads and will sometimes use tweezers if I'm a kernel or 2 light / heavy. The similarities between the 2 are striking - down the mix of kernel sizes and how they are cut. Just an observation
image.jpegLet's go Brandon!
Comment
-
-
Originally posted by StoneHendge View PostI'm sure your velocity was pretty good and your SDs were absurd. Best I could get was 3/4" to 7/8" out of my recipe above and 30.8'of CFE shoots under 1/2" so I went in that direction.
I started using Norma 202 for 308 a couple of years ago in the powder drought. When I bought my lb of AR Comp, It wasn't too hard to figure out who made it for Alliant. I dusted off the Norma 202 to try in 22 Nosler earlier in the week. I trickle onto a balance beam for precision loads and will sometimes use tweezers if I'm a kernel or 2 light / heavy. The similarities between the 2 are striking - down the mix of kernel sizes and how they are cut. Just an observation
[ATTACH=CONFIG]9298[/ATTACH]
Comment
-
Comment