AR Comp and SMK 120 - looking high and low for some data

[doktarZues]

I got caught with my pants down and running low on IMR 8208. This powder worked extremely well for me, charge weight didn't appear to matter too much (a little tighter in the hotter end). Well boo hoo I've decided to look elsewhere. I did manage to score a jug of AR Comp when I saw things getting crazy. Searching high and low for data. The only official load data I've been able to find for any 120gr bullet is Speer 120gr gold dots - their max is 25.3 grains of Ar Comp. Nothing official for Ar Comp and SMK 120s.

Unofficial/forum-reported data on Ar Comp and SMK 120 - I've seen quite a few references of max charges hitting low 26s, and at least two over 27, one 27.5!!

Obviously I will be doing the right thing and starting low and working my way up.

Can anyone point me to ANY official data source for Ar Comp and SMK 120s? Or even just general Ar Comp "official" load data for 6.5 grendel? (I've got a dozen or more different .264 bullet types I'd like to try with Ar Comp, but the SMK 120 is what I'm most interested in.)

Also interested in hearing from Ar Comp fans, your experience, your load data. Thanks folks

[grayfox]

The 120-123 class bullets that I've tried ARC in usually top out at 28 grs. I have tried the 120 pro hunter, which Sierra lists the same data for as for the 120 Hpbt... But they do not list ARC in their page.
The Grendel Handbook has the pro hunter with 28.0 grains in it in the load data from shooters, but this is one unofficial source (as mine also is btw).

Sierra does list several powders however.

Be aware that ymmv. If you start low, I'd suggest backing down to maybe 26.0 and shoot over a chrony, do a ladder to watch MV data.

[VASCAR2]

I bought some AR Comp but haven’t had time to test it. I plan on using my chronograph and will watch the velocities as I work up. I think I should be able to get close to or a little over 2400 FPS out a 16 inch with 120-123 grain bullets, around 2425-2475 out of 18 inch, 2500-2525 with 20 inch and 2550-2600 in my 24 inch barrel Cz 527. My other barrel lengths are all in AR-15’s. I have a 12 inch PSA pistol and I think I can get 22225-2250 FPS with 120-123 grain bullets and AR-Comp.


I know Speer list 25.3 grains of ARC with a 120 grain gold dot at 2418 FPS out of 24 inch universal receiver. I’ve read Gold Dots build pressure faster than many cup and core bullets. By ARC burn rate and velocity posted by forum members I think Speers data is conservative. I wish the actual pressure was stated for the begining and max charge. Western list the actual pressures and I wish more data provided the pressures.

I have written Alliant a couple of times requesting 6.5 Grendel data. It can hurt to try sending them an email, can’t hurt to show them there is interest.

[VASCAR2]

I just emailed Alliant again requesting load data for their powders for the 6.5 Grendel.

[muvef]

I believe Johnny's Reloading Bench on YouTube used it several times with that weight bullet.

[grayfox]

I did 2 small load groups of gold dots with ARC, couple of months ago in my RAP and based on that limited shoot I would limit myself to 28.0 max for that bullet also. but do it over a chrony.

[doktarZues]

The 120-123 class bullets that I've tried ARC in usually top out at 28 grs. I have tried the 120 pro hunter, which Sierra lists the same data for as for the 120 Hpbt... But they do not list ARC in their page.
The Grendel Handbook has the pro hunter with 28.0 grains in it in the load data from shooters, but this is one unofficial source (as mine also is btw).

Sierra does list several powders however.

Be aware that ymmv. If you start low, I'd suggest backing down to maybe 26.0 and shoot over a chrony, do a ladder to watch MV data.

How similar are the SMK 123 to the 120? Seems there is more data out there for those. When you say "top out," that just watching for velocity to hit around normal book tops and pressure signs?

[doktarZues]

Jeez.. the Speer load data calls max at 25.3 for the 120gr gold dots. That's part of my confusion, people seem to be shooting this stuff way over the max of what little data seems out there.

[doktarZues]

I believe Johnny's Reloading Bench on YouTube used it several times with that weight bullet.

He did the speer gold dots.. and fired up to 25.3. Granted he said it could go further, the brass looked fine.

[Rugerfan.64]

I think you will be pleased with it. I know I am. I shoot it out of my AR , I'll have to dig up some data, I have posted previously Shooting Times data pictures on here in other threads. I will just tell you that I fired 50 rounds of that same Sierra 120 MK at 100 yds and only had one 5 shot group go over an inch. Well, everyone must be doing homework and the pic won't load. I'll try and get it to you in a PM.

[Grendelshooter]

He did the speer gold dots.. and fired up to 25.3. Granted he said it could go further, the brass looked fine.

He also shot the 120 ELDM I believe

[damastas]

I've fired the 120 SMK with AR Comp with great results. Did a test with 26.0,26.3,26.6,26.9 and saw no pressure signs. I stopped there as my MV was getting higher than I wanted, around 2450 with an 18" barrel, and found good nodes around 26 and 26.3.
My pet load for it is Hornady Brass, CCI 450, 26.3, COL 2.24, with a MV of around 2400 and I consistently shoot sub MOA with it. The bottom right and bottom middle were unrelated loads.

[ATTACH=CONFIG]15851[/ATTACH]

[newb]

My stuff is packed as I am moving so just some brief input from memory.

I used quickload to get base values. SMK was pretty close to predicted. I think Hornady ELD showed pressure well before predicted in my ladder loads.

22” JP barrel.

New Starline brass. 2.26 coal

I had to cut the day of gathering data short because the brightness was causing grief to my chrono. (Have since picked up a lab radar)

To my memory, AR Comp and 120 gr smk worked very well. I don’t remember the ladder loads and which produced what. On the high end one was 2600 FPS + with sub MOA. No pressure signs, but noticeable more recoil than the rest.

Better groups and velocity than Hornady ELD. I think ELD might have been 120 gr?

For what ever reason the lighter ELD started to show pressure signs a tad above the velocity of what the factory 123 GR ELD produce = 2510 - 2550’ish. Maybe 50 FPS more than factory showed signs where quickload simulated it shouldn’t. But I start below and work up so all was well as I didn’t keep trying hotter.

I know I haven’t tried 107 TMK, hopefully I’m not confusing Berger in there, but I don’t believe I did any loads for those yet.

[VASCAR2]

I just emailed Alliant again requesting load data for their powders for the 6.5 Grendel.

Here is the question I sent to Alliant and their response.

The only published data I can find for AR Comp is the Speer online source. AR Comp seems well suited for use with the 6.5 Grendel but there is very little data. AR-Comp looks suitable for bullets from 90 grains to 130 grains in the 6.5 Grendel. The 6.5 Grendel is gaining in popularity and AR Comp is desired because it pretty stable in different temperatures. Please test your powders for the 6.5 Grendel and publish your data. I believe other powders you produce are suitable for the 6.5 Grendel but we need load data.


Response from Alliant.

I have approached this question numerous times with the lab. But, there has as of yet been no data available from us for the Grendel.
I will again pass this onto the team.
Thanks,
Duane V. /Technical Service Representative
2299 Snake River Ave.
Lewiston, ID 83501
Alliant/Blazer/CCI/Speer
866-286-7436

[Drillboss]

Jeez.. the Speer load data calls max at 25.3 for the 120gr gold dots. That's part of my confusion, people seem to be shooting this stuff way over the max of what little data seems out there.

To quote Bill Clinton, I feel your pain. To the best of my knowledge, Speer bullets has the only published pressure tested data for AR-Comp for the Grendel. For the 120 gr pills, the only data is for the 120 gr Gold Dot. That data shows lower and slower for all the powders tested. I don't get it.

I played with some ratio numbers using 8208 data versus Power Pro Varmint data that indicated Sierra's max load for AR-Comp should be about 27.5 grains based on those ratios. Without pressure data, who really knows? I tried AR-Comp with Hornady's 123 gr SST's and my best group turned out to be at 27.4 gr.

That said, since Alliant and Speer are sister companies, Alliant probably won't be giving us data for any other 120 gr bullets. Like I indicated before, that Gold Dot data seems weird. We should probably be pushing Hornady, Barnes, and Sierra to test AR-Comp with their bullets.

[grayfox]

A little background, Alliant made AR comp to be a more temp-stable version of RL-15... which they were able to do, but in the process it came out a little faster than RL-15. Which turns out to be fine for the grendel, IMO.
I found this tidbit somewhere direct from Alliant, just forget where that was.

[Mesa1978]

27.7 grains magazine length, yes compressed, 450 primer, works in both my Shilen from Midway and PF Lilja, Hornady or Lapua brass. Good grease stains on target, but quite accurate at the same time.

[Grendelshooter]

Tagging this for later...

[Gtscotty]

I don't have any official data on AR-Comp in the Grendel, but having used it in .308 with good results, I started playing with it in the Grendel in Quickload. Velocity results were good, and testing showed good accuracy as well. After some load development with 123gr ELDs and 129gr Interlocks in my lightweight 16", I wound up with the loads below. Pressure seems ok, and the velocities are similar to those predicted in QL, and are pretty good for this rifle.

[FLshooter]

I have a ridiculous amount of AR Comp. Over 14lbs. I wanted to try it for my 6.5 Grendel.I couldn’t find load data. So I went to space Coast bullets and I asked the owner. He told me with ELDM 123g bullets,I should start at 26.5g AR Comp.
I started at 26g AR Comp and worked it up to 27.5g. 27.3g is the sweet spot for my rifle.Did not try it yet with 120 g SMK bullets yet, Because I already have a load worked up w/H335 . But,if you work up from 26g w/120g SMK,you’ll be good.