Question on velocities 300 Win Mag

[six pack]

All of the powders listed are good for 300WM.....I've tried them all and had good luck. However, let me throw another one into the mix. I strongly recommend Ramshot Magnum and have settled on it in my 300WM. I worked up a fairly mild load of 82g in a Win case using Federal 215 primers under a 180g Nosler AB about .030 off. The rifle seems to love it as the velocity averages 2990 fps and the numbers are consistently single digits.

 

[Wingnut00]

My personal opinion is H-1000 is the golden ticket for the 300 Winchester. I've completely burned up two barrels on mine and is is the clear winner for bullets over 180 grains. Again that's just my opinion but I'll stick to it.

 

[vancewalker007]

Another new powder that is very temp stable and will fill the case nicely is IMR 8133. And as suggested, H1000 should settle your ES down. I've easily pushed my ES down in the low teens in my 6.5 PRC using H1000 and very careful reloading. Even if you can get down in the 20s you'll have something. You don't noticed major elevation issues at 1000 yards until you get over around 20-25.

Make sure your case dimensioning is consistent, ie. consistent base to shoulder length, base to case mouth length, neck tension (via correct bushings). Make sure your charges are at least on the same 1/10 grain. Also you need to be sure you're not loading on a velocity jump point and that you're loading in a flat velocity node.

 

[Buellbeast]

Ok that makes sense, I'm going to try a new powder and ensure the fit on the case is constant. I appreciate the advice!!!

 

[Buellbeast]

Really, I'm in a massive learning phase, and all of this is excellent info.

 

[vancewalker007]

Really, I'm in a massive learning phase, and all of this is excellent info.

You'll sort it out. The 300 WM has a lot of accuracy potential.

 

[tbrice23]

Really, I'm in a massive learning phase, and all of this is excellent info.

I'm willing to bet your case isn't very full with your Rl17. You really need to use a powder slow enough to get you at least 85% case fill to have uniform combustion. H1000 retumbo Rl25 might do it. I run wide open with RL25 and 185 Hybrid Targets at 3230 fps. My ES is about 10.

 

[Frog4aday]

What powder measure are you using? A Lee 'mechanical' scale isn't the most precise thing. Ideally you'd have a quality 'beam' scale (older RCBS units were quite good) and a digital scale so you could throw a charge and then verify on two different scales to eliminate inconsistent powder charges as the issue. For example, many people use an RCBS Chargemaster Lite to throw their powder, then they re-verify on a beam scale before putting it into the case.

I'm sure folks are on the right track with the need to find a more temperature stable powder, but the variation you described seemed pretty large unless you developed the load at 5 degree Fahrenheit and then shot it again at 95 degrees. Figure one FPS change in velocity per degree of temp (in Fahrenheit) as a general rule of thumb for a 'temp sensitive' powder like R17 or R19. Getting more variability than that? Something else is probably going on.

Cases are all the same headstamp? Are you annealing? Do they have the same number of firings on them (i.e., all once fired brass or twice fired brass?) Are you cleaning your brass with steel media vs. corn cob media? A super clean case mouth (i.e., bare brass vs. a case with some carbon still in place) is more likely to 'stick' to the bullet, so as the ammo sits longer, you get more 'pull tension' than when you first loaded it.

Just spit-balling some ideas to go with the potential powder issues.

 

[Buellbeast]

What powder measure are you using? A Lee 'mechanical' scale isn't the most precise thing. Ideally you'd have a quality 'beam' scale (older RCBS units were quite good) and a digital scale so you could throw a charge and then verify on two different scales to eliminate inconsistent powder charges as the issue. For example, many people use an RCBS Chargemaster Lite to throw their powder, then they re-verify on a beam scale before putting it into the case.

I'm sure folks are on the right track with the need to find a more temperature stable powder, but the variation you described seemed pretty large unless you developed the load at 5 degree Fahrenheit and then shot it again at 95 degrees. Figure one FPS change in velocity per degree of temp (in Fahrenheit) as a general rule of thumb for a 'temp sensitive' powder like R17 or R19. Getting more variability than that? Something else is probably going on.

Cases are all the same headstamp? Are you annealing? Do they have the same number of firings on them (i.e., all once fired brass or twice fired brass?) Are you cleaning your brass with steel media vs. corn cob media? A super clean case mouth (i.e., bare brass vs. a case with some carbon still in place) is more likely to 'stick' to the bullet, so as the ammo sits longer, you get more 'pull tension' than when you first loaded it.

Just spit-balling some ideas to go with the potential powder issues.

I'm using RCBS Chargemaster and just loaded 12 more rounds with RL22 I used an additional scale to eliminate the possibility of a powder error. I also checked the resizing and depriming pin to make sure it is .306. I'll see how it shoots with that powder and now I'm researching annealing. Looks like I can get into that process at a reasonable price. Some of the machines are pretty expensive, and some not too bad. Thanks for the advice.

 

[ZAK13]

I've been using the IMR h4831, it's a more stable powder and has given me much better consistency in velocity over a wider temperature range. I've heard, but never tried for myself H1000 is another great powder for the 300WM when using heavier bullets, personally I found the Barnes 180gr T-TSX works best for me.

 

[Vol1975]

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.

Can be a lot of reasons but rl 17 in my opinion is a fast burning powder for a magnum. Case fill and how the powder lays in the brass will affect some, brass fill or same type of brass, condition of the powder, and neck tension. Every thing can add up to have a variance on constant speed. Personal I would choose a powder that would give u a more full case capacity. I run at least .002 of neck tension on my bullets and run a good brass that is the same in weight and maker.
Also if you have shot the brass a lot I would consider annealing the brass. Again neck tension plays a role.
Rl23 pretty good powder for that weight.
H1000 has been good for me and many would say is a staple for the magnums. The burn rate around h1000 is where I would look.

I have run h4831 with good success but had a lower ES with a slower burning powder than 4831sc.

Anyway there is a lot of information out their on the 300win

 

[Buellbeast]

Can be a lot of reasons but rl 17 in my opinion is a fast burning powder for a magnum. Case fill and how the powder lays in the brass will affect some, brass fill or same type of brass, condition of the powder, and neck tension. Every thing can add up to have a variance on constant speed. Personal I would choose a powder that would give u a more full case capacity. I run at least .002 of neck tension on my bullets and run a good brass that is the same in weight and maker.
Also if you have shot the brass a lot I would consider annealing the brass. Again neck tension plays a role.
Rl23 pretty good powder for that weight.
H1000 has been good for me and many would say is a staple for the magnums. The burn rate around h1000 is where I would look.

I have run h4831 with good success but had a lower ES with a slower burning powder than 4831sc.

Anyway there is a lot of information out their on the 300win

Thank you

 

[Buellbeast]

So I just some RL 23 and H1000. I see in the Nosler load data a starting point H1000 but nothing for the RL 23. Does anyone have a good safe starting point? I'm thinking this will start to fix my ES issue. Also, resized all the necks to .002 and things are starting to look good.

 

[L.Sherm]

Alliant has it on there website.