Bullet jump

[mxmaniac2004]

I'm having trouble getting my grendel to shoot well. About the best I can manage is 1-1.25 inches at 100 yards. My first load: 123 scenar over 8208 shot the slightly under MOA, but is running really slow (2220 fps if i remember correctly) Unfortunately my chamber has a very long throat, I'm having to jump the bullets 123 scenars .085 to fit in the magazine.

I'm running lapua brass, have a 18" Brux barrel, and have tried 8208 and H335 powder.

Anyone have an idea of something I could try? I have some 107 Sierra matchkings I can try. I considered loading some bullets closer to the lands, but a single shot AR has zero appeal to me.

Thanks for any advice.
Chris

[Buster]

Do you have a baseline of shooting factory loads like 123gr Hornady AMAX?

[mxmaniac2004]

I did shoot 2 boxes of 123 amax factory with nearly identical results. Just slightly larger than 1 inch.

[Nick]

What optics ate you using? I was having trouble with mine, firing about the same size group. Burned thru 2 boxes of a-maxs. Tore down scope and rings, torqued everything and was dead on after that. Didn't do anything out of ordinary first time I set scope but something was just off. Anyhow, not saying that is the problem but worked for me.

[mwilkins]

I have two loads worked up right now using both 123 Scenars and 120 Bergers with 8208. Both are jumping almost .100 due to magazine seating depth. My new Magnetospeed V3 is scheduled to be delivered today. Once I get home, I will post up how much XBR is being used in both loads and get new velocities this weekend. Hornady Brass, Wolf Primers. Rounds being sent down a 24" tube.

[mxmaniac2004]

Im using an IOR 2.5-10x42 in a Larue mount. I suspected the optics problem and checked the torque on everything with no change in results. I even went so far as to swap scopes and try again, a have let 2 other people shoot it to prove its not the nut behind the trigger. Not that its shooting terrible groups, but this is my first foray into gas guns; I'm more accustomed to bolt guns and like precision.

[lrgrendel]

What upper or make of rifle is it? I have an AA over watch 24" and 8208 or 123 scenars don't work well. 123 Amax with Acc 2520 or Varget works for me. Also try CFE . I really don't understand why a long throat is made??

[mxmaniac2004]

Its a dpms upper that I had my gunsmith chamber the Brux barrel for.

[LRRPF52]

Its a dpms upper that I had my gunsmith chamber the Brux barrel for.

What reamer did he use?

Are you using a torque wrench for your scope rings?

[Sniper338]

How many round are down the barrel? Get at least 100 to 200 down it first before you try to find a load... i have several brux barrels and never could get them to shoot right away... get a good copper fowl laid out in it too.. as in dont clean it much...

if its an 8 twist barrel or 8.75 twist....Use 123 Amax bullets.... if its 9 or 10 twist then try lighter bullets... and reloader 15 is the shit for me and my grendel... it wouldnt shoot any other powder at all.... start at 26 grains and work up slowly.. use cci or federal match primer. Watching primers for signs of pressure...

[acourvil]

I have two loads worked up right now using both 123 Scenars and 120 Bergers with 8208. Both are jumping almost .100 due to magazine seating depth. My new Magnetospeed V3 is scheduled to be delivered today. Once I get home, I will post up how much XBR is being used in both loads and get new velocities this weekend. Hornady Brass, Wolf Primers. Rounds being sent down a 24" tube.

I'd be interested in your load data. My scenar 123 load is 28.0 XBR, lapua brass, cci 450, OAL 2.251, getting 2500fps out of a 22" barrrel. Working up a load for the Barnes 120s next.

[jurassic]

[QUOTE=LRRPF52;105223]What reamer did he use?


Knowing the answer to this question will probably shed some light on the problem. If you can't load to a sufficient length to get acceptable results because of magazine limitations you could be in trouble. Granted there maybe another issue, but I would load some long and single feed to eliminate that as the problem.

[mwilkins]

I'd be interested in your load data. My scenar 123 load is 28.0 XBR, lapua brass, cci 450, OAL 2.260, getting 2500fps out of a 22" barrrel. Working up a load for the Barnes 120s next.

Same load on the XBR. Running 27.5 on the Berger 120's and 28.0 on the 123 Scenar's. Hornady brass, Wolf Magnum Primers. Both seated to mag length at 2.230. Both loads are getting me consistent .750" to .850" groups at 100 yds but I don't believe the numbers on the loads are accurate through the chrono that I borrowed so I ordered the Magnetospeed. Should get some solid numbers this weekend hopefully. I believe there is room for group size improvement with a little more work. Haven't played with any other powders thus far either.

[acourvil]

Thanks!

The MagnetoSpeed definitely is more accurate than a lot of the light sensing chronos. I have a ProChrono and the MagnetoSpeed, and the ProChrono varies quite a bit in different light conditions. It's good enough for quick comparisons, but if you want accurate speeds for doing range cards the MagnetoSpeed is much better.

[Dr. Lee]

Just curious, what trigger do you have in your rifle ?