260 Rem Powder Change

[d_train821]

Hey everyone. so i have a bit of a different loading strategy than i usually see on here. i found that if i use necked down 308 lake city brass, i can push my rounds the same speed as if i was running lapua brass, but with less powder charges. IE: if i load lapua cases and 139 scenars and 43.5 of H4350 i am getting about 2895fps. i load the lake city brass to 42.4 and get 2889fps, with a sd of 4.5. only thing i can think of is the thicker brass causes more pressure build up. i dont have to trim it, because when i size it down, the case is about .01 shorter than sami specs so it also saves time. this is with my bolt gun 26" bartlein 1:8 twist

now, the big question i have. i recently got a 260 gas gun, 22" barrel and rifle length gas tube. i did a load development with 130 berger AR OTMs and settled with 41.8 H4350, and they push at 2770fps with an SD of 4, ES of 12. its all fine and dandy, but i want to get a little more velocity without bumping down to the 120s. if i switch to Varget powder, will the different burn rate help push them a little faster? if so, should i start my load development at the same as the 4350 (40gr).

 

[Defender3]

FWIW - The Berger reloading manual lists the 130gr Match VLD Target with Varget: Min - 33.5gr @2481; Max - 37gr @2703; there is no load for a 120gr or a 140gr with Varget.

Running QL with the max Varget load and the Berger 130gr AR Hybrid OTM G7 suggests 2621fps out of a 22" barrel with pressure listed at 49778. Raising the charge to, for example, 38gr only gets you to 2683fps, but pressure is near max at 53514. Tolerances or OAL could put you over max. To get 2810FPS requires 40.1grs and is over max pressure at 62252. The 120gr class of Bergers is only reaching 2860fps with max loads across several differing powders.

Your mileage will vary so proceed safely.

FWIW II - I have a 260 gasser and it prefers a bit slower velocity (low 2700s) versus higher. I get better accuracy and less hammering from the BCG (running a H2 buffer and a red spring). I can only imagine the port pressure you could be getting with a rifle length tube. Also, the Berger manual suggest the 260 prefers a medium to slower powder for the best velocity and accuracy. I primarily use H4350 with Hornady 130gr ELD-Ms, so I don't have comparable data answering your original question.

 

[vinsonr]

Please do not start a new powder load at the same as any other powder. This can be dangerous.

http://www.hodgdonreloading.com/data/rifle

Hodgdon lists the max for 130 gr bullets at 37.2gr Varget. H4350 will likely provide higher velocities than Varget.