Expected mv for 185gr

[Jase PTRC]

Hello im just wondering what would be a realistic maximum muzzle velocity for a .308 using 185 gr projectile. Barrel is 30 inches long 11 twist. Thanks in advance

 

[watercam]

With Varget I was getting 2660, with H4350 I was up to 2750 but best accuracy was closer to 2700.

 

[Ned Ludd]

That will largely depend on how much freebore your chamber has and how you intend to do your load development. If the throat has enough length that you can seat the 185s such that the boattail/bearing surface junction is above the neck/shoulder junction AND you load to Optimized Barrel Time (OBT) nodes, you can expect somewhere in the neighborhood of 2725-2750 fps with Varget , and 2750-2775 fps with H4895 at the accuracy node (Node 4 from Chris Long's OBT table). If your using another approach such as ladder testing or OCW, there will be other accuracy nodes available at slightly higher and lower velocities.

I have a .308 F-TR bolt gun that has .085" freebore, which is pretty short for 185 Juggernauts. The boattail/bearing surface junction is just barely above the neck/shoulder junction. A load optimized for that rifle using Varget in regular Lapua .308 brass gives me 2720 fps. With H4895, loads will generally tend to be about 20-30 fps faster at the sweet spot, but they also run slightly higher pressure. In another rifle that has .180" freebore, the respective velocities in Lapua Palma brass with Varget and H4895 are 2750 and 2780 fps. The longer freebore and slight increase in case volume of Lapua Palma brass over standard allows you to get slightly higher velocity at the same, or even moderately reduced pressure. Both of these rifles have 30" barrels.

Bottom line is that you can likely expect somewhere in the range of 2700-2750 fps with Varget, and 2725-2775 fps with H4895 from a 185 out of a 30" barreled rifle. These are "generalized" estimates only, but are fairly common velocity ranges for 185s in 30" barrels with those powders. Your rifle may or may not fall inside that window. Other powders may give different results, such as IMR4064, IMR4320, PowerPro2000MR, etc. Just remember that increased velocity comes at the expense of higher pressure and reduced brass life. Start low, work up in safe increments, and your rifle will tell you where it wants to shoot. Extra velocity is nice, but good precision is where you want to be. Sometimes you can have both, but I'd take the good precision with slightly lower velocity every time. An extra 50 fps velocity doesn't mean very much if the precision is mediocre or poor.

 

[rmist]

With my 30" barrel and 44.5 gr. varget Lapua palma brass I can only achieve 2685 fps in a 10 twist barrel. Verified over 2 different chronographs a CED I I and a Ohler 35. Shoots very well. Just seems slow for that much powder.

 

[jsthntn247]

With my 30" barrel and 44.5 gr. varget Lapua palma brass I can only achieve 2685 fps in a 10 twist barrel. Verified over 2 different chronographs a CED I I and a Ohler 35. Shoots very well. Just seems slow for that much powder.

My new 308 is shooting 44.4gr of varget at 2685 with the 185's also. 32" 10 twist in Palma brass. It shoots aight

 

[Jase PTRC]

That will largely depend on how much freebore your chamber has and how you intend to do your load development. If the throat has enough length that you can seat the 185s such that the boattail/bearing surface junction is above the neck/shoulder junction AND you load to Optimized Barrel Time (OBT) nodes, you can expect somewhere in the neighborhood of 2725-2750 fps with Varget , and 2750-2775 fps with H4895 at the accuracy node (Node 4 from Chris Long's OBT table). If your using another approach such as ladder testing or OCW, there will be other accuracy nodes available at slightly higher and lower velocities.

I have a .308 F-TR bolt gun that has .085" freebore, which is pretty short for 185 Juggernauts. The boattail/bearing surface junction is just barely above the neck/shoulder junction. A load optimized for that rifle using Varget in regular Lapua .308 brass gives me 2720 fps. With H4895, loads will generally tend to be about 20-30 fps faster at the sweet spot, but they also run slightly higher pressure. In another rifle that has .180" freebore, the respective velocities in Lapua Palma brass with Varget and H4895 are 2750 and 2780 fps. The longer freebore and slight increase in case volume of Lapua Palma brass over standard allows you to get slightly higher velocity at the same, or even moderately reduced pressure. Both of these rifles have 30" barrels.

Bottom line is that you can likely expect somewhere in the range of 2700-2750 fps with Varget, and 2725-2775 fps with H4895 from a 185 out of a 30" barreled rifle. These are "generalized" estimates only, but are fairly common velocity ranges for 185s in 30" barrels with those powders. Your rifle may or may not fall inside that window. Other powders may give different results, such as IMR4064, IMR4320, PowerPro2000MR, etc. Just remember that increased velocity comes at the expense of higher pressure and reduced brass life. Start low, work up in safe increments, and your rifle will tell you where it wants to shoot. Extra velocity is nice, but good precision is where you want to be. Sometimes you can have both, but I'd take the good precision with slightly lower velocity every time. An extra 50 fps velocity doesn't mean very much if the precision is mediocre or poor.

Thankyou this was the info i was chasing. My barrel has not been chambered yet i only just dropped off the barrel and action yesterday. I was mostly loking for a baseline so i could run some thing through my AB program and compare to the 155gr pills im shooting now.

 

[Zero333]

Winchester brass and a compressed load of H-4350 is a speeding ticket.