Question on velocities 300 Win Mag

[Buellbeast]

I'm shooting a 300 Win Mag and have really found a love for reloading. Im loading using RL 17 at 68gr. each and the bullet I'm shooting is a 190gr ACCUBOND LR in hornady brass. My groups are nice and tight but my velocities are varied by as much as 100 FPS. All cases are measuring the same, and I'm measuring off the OGIVE at .030" off the lands for the bullet. The load data says I should be around 2960, but have seen all the way up to 3099fps, and as low as 2900fps. I'm measuring speeds with a lab radar, and am not sure why the speed varies so much. Looking for any advice.

 

[Buellbeast]

I'm shooting a 300 Win Mag and have really found a love for reloading. Im loading using RL 17 at 68gr. each and the bullet I'm shooting is a 190gr ACCUBOND LR in hornady brass. My groups are nice and tight but my velocities are varied by as much as 100 FPS. All cases are measuring the same, and I'm measuring off the OGIVE at .030" off the lands for the bullet. The load data says I should be around 2960, but have seen all the way up to 3099fps, and as low as 2900fps. I'm measuring speeds with a lab radar, and am not sure why the speed varies so much. Looking for any advice.

One last thing to add us I'm using federal 215 primers

 

[L.Sherm]

How warm are the temps you shooting in, RL17 is not very temp stable.

 

[elkaholic]

How warm are the temps you shooting in, RL17 is not very temp stable.

Especially if they sit in a chamber and heat soak for a while!

 

[L.Sherm]

Different Internal volumes of brass, different primer, neck tension alot of things can contribute to high ES

 

[Buellbeast]

Ok, the temps are high 80's to low 90's in the shade. I can see that the neck tension could be one of my issues, and I could try another powder. I've heard RL 23 is really temp stable, so maybe I'll try that one.

 

[L.Sherm]

RL23 is good, I'd give it a shot.
H1000 is very stable alot of guys have had good luck with the heavys in a 300WM

 

[Buellbeast]

Yeah, I've also seen a lot of guys using H1000. The more I think about it, is crimping the case an important step for ensuring the pressures remain the same and in-turn the muzzle velocities the same?

 

[L.Sherm]

No, consistent neck tension is better.
I like 90 percent or better case fill I think it helps with ES.

 

[elkaholic]

Yeah, I've also seen a lot of guys using H1000. The more I think about it, is crimping the case an important step for ensuring the pressures remain the same and in-turn the muzzle velocities the same?

NO! Just run about .002" fit on the bullet and keep your cases trimmed. Annealing can help too.

 

[L.Sherm]

I would work on a slower powder first and see if that helps

 

[Buxndiverdux]

.002 Neck tension, H1000, RL26, N570 or H4831SC. That is where I would start, one or more of those powders will probably work well.

RL26 and N570 are hard to find right now.

 

[Mike AVM]

Your likely going to need to shoot some loads around 68 grains to see if ES improves. I've shot a lot of RE17 and don't have ES issues. You really need a slower powder like RE23/26 in the 300WM. I shoot RE17 in shorter mags like the 338 WM. H1000 is also a good choice above 180 grains.

 

[HobieH3]

.002 Neck tension, H1000, RL26, N570 or H4831SC. That is where I would start, one or more of those powders will probably work well.

RL26 and N570 are hard to find right now.

I saw a post somewhere that the N570 is hitting dealers