Planning on building a AR in either 6.5 CM or .260 Rem. I pretty much settled for a 20" barrel what kind of muzzle velocities are you guys getting with what loads?
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Muzzle velocity for a 20" barrel.
- Thread starter Lonewolf762
- Start date
I Have a 20 inch Tikka 260 bolt gun and I am getting 2715 FPS with 43.6 grains of H4350 under a 140 Berger. I'm using Lapua brass and BR2 primers.
I think you might be hard pressed to get that in a gas gun though.
I think you might be hard pressed to get that in a gas gun though.
Probably expect about 120fps loss from the barrel length then factory advertised velocities. However that is just a very rough round about estimation. Every barrel is different.
I dont have 20" numbers but here are numbers for my 22" Bartlein 1:8 6.5cm Semi
H4350/140 ELD-M
41g-2650
41.3g-2649
41.6g-2684
41.9g-2693
42.2g-2721
42.5g-2737
42.8g-2744
H4350/123 Lapua Scenar
43g-2837
43.2g-2847
43.4g-2859
43.6g-2864
43.8g-2874
44g-2888
H4350/130 ELD-M
43g-2738
H4350/140 ELD-M
41g-2650
41.3g-2649
41.6g-2684
41.9g-2693
42.2g-2721
42.5g-2737
42.8g-2744
H4350/123 Lapua Scenar
43g-2837
43.2g-2847
43.4g-2859
43.6g-2864
43.8g-2874
44g-2888
H4350/130 ELD-M
43g-2738
My h4350 and 140 amax out of a 22" Krieger barreled gas gun is very similar to the numbers posted by Padom. 42.0 and ~2720 fps.
I have seen about 25fps per 1" of barrel length with a 308 that I cut the barrel from 26" to 22" (lost 100fps on my 175gr/4064 loads). I also have a 260 Rem700 with a 25" Bartlein 1:8" barrel and a 260 GAP10 with a 20" Bartlein 1:8.2" barrel. 42.6gr of H4350 and a 140gr SMK runs 2820fps in my R700 while the same load but in SSA brass instead of Lapua runs 2710fps in my GAP10. The same lot of Prime ammo thru each rifle shows similar velocity loss to my 308 experience.
