Posts: 52
Threads: 15
Joined: Nov 2015
Barrel being used is the Odin Works 20" with Type II bolt. I was having short stroking issues previously and discovered the gas port was drilled to small and had to ream it out to what they currently drill their gas ports to and it works flawlessly now. I previously tested Ramshot xterminator with the 123gr but had no success.
Testing was using 5 shots for each charge @ 100 yards and the results are average velocities:
25.5gr- 2098fps
26.0gr- 2154fps
26.5gr- 2196fps
27.0gr- 2235fps (best groups see pic below)
27.5gr- 2283fps
28.0gr- 2332fps
28.5gr- 2376fps
Don't worry about that little guy off to the left
![[Image: 20160220_133939.jpg]](http://s10.postimg.org/sl9fslww9/20160220_133939.jpg)
Posts: 21
Threads: 2
Joined: Feb 2016
Looks like we are losing about 150 fps. by giving up 4" of barrel length.
http://www.nosler.com/nosler-load-data/65-grendel/
Posts: 1,613
Threads: 24
Joined: Sep 2014
Outstanding group!
Vsaluki Wrote:Looks like we are losing about 150 fps. by giving up 4" of barrel length. http://www.nosler.com/nosler-load-data/65-grendel/
Not so sure about that. We frequently see significant variations of velocity when going from one chamber to another chamber cut with the same reamer. The variations get larger when there is throat wear, tweaks to reamer design, and so on.
For example, we see in Volume 2 of the
6.5 Grendel Reloading Handbook with 27.0 gr TAC and the 123 gr AMAX:
- 16" Bbl 2218 fps
- 24" Bbl 2397 fps
While the OP velocity is about 70 fps below the trend line suggested by these loads, that difference is within what might be called normal barrel to barrel variation.
Ammoguide.com has more loads and we see greater variation in the reported velocities.
shootersnotes.com
"To those who have fought and almost died for it, freedom has a flavor the protected will never know."
-- Author Unknown
"If at first you do succeed, try not to look astonished!" -- Milton Berle
Posts: 289
Threads: 14
Joined: Dec 2015
I would try another powder. You should be in the 2500 fps range with a 20" barrel. With 8208 in an 18" I'm getting upper 2400's.
Posts: 482
Threads: 40
Joined: May 2015
Yeah, TAC produces slower velocities. 28.5 grains and a 120 smk shot 1/2 moa out of my 18" BHW barrel but was in the low 2400 fps range. My AR comp load averages 2500 fps. It is an accurate powder though.
Posts: 21
Threads: 2
Joined: Feb 2016
Cornbread Wrote:I would try another powder. You should be in the 2500 fps range with a 20" barrel. With 8208 in an 18" I'm getting upper 2400's.
According to these Nosler numbers, 8208 gives about 40-50 ft/sec more than TAC when you extrapolate to equal loads. So I was still surprised at how much more you were getting with the 18" than he got with the 20".
http://www.nosler.com/nosler-load-data/65-grendel/
Posts: 34
Threads: 6
Joined: Sep 2014
I shot the Hornady boxed ammo 123SST, and the first 5 rounds were chrongraphed at 2610,2603,2609,2602,and 2599. This was out of a 24" bolt gun. Then I tried a few shots I had leftover (123 Amax) from a previous shoot, 31 grains of CFE223 and I got 2535,2537,2546,2542. I was using a magneto speed sporter chrony and it worked great. Very accurate loads as well.
Posts: 289
Threads: 14
Joined: Dec 2015
Vsaluki Wrote:According to these Nosler numbers, 8208 gives about 40-50 ft/sec more than TAC when you extrapolate to equal loads. So I was still surprised at how much more you were getting with the 18" than he got with the 20". http://www.nosler.com/nosler-load-data/65-grendel/
I think that the consensus is that the nosler data is fairly weak ( which is the opposite of my usual experience with their data) for the grendel. In fact their max load is less than hogdons wth similar weight bullets. Also, the type of rifling can affect pressure and velocity. from what I have seen for data on this site and the grendel load books mid to upper 2400's is typical for 123 gr amax, sst with 8208 and 18" barrel.
