Another reloading question.

[RAF]

As I said on the other post, when I was testing the new 300 WSM, the groups all went south for the last 2 test loads of 65 and 65.5 grains. Some shots were over 8 inches from zero. Just wondering if it could have anything to do with already having fired over 40 rounds and had not cleaned the bore. Could the fouling have built up to the point that it would have affected groups?

[whyohe]

anything is possible. maybe your gun just doesn't like that load. one way to find out is to thoroughly clean it and shoot those loads again

[bubba]

moving 8 inches is pretty erratic, I would guess that its a bad load for that rifle.......

[RAF]

That shot would have had me scratching my head if the rest had been close, but they weren't. I know I didn't pull it so shooter error is out. All I can think of is the rifle doesn't like that powder. I have a couple of others I want to try and my first stop, shopping, wasn't good. Didn't have either in stock and don't know when they'll get any. Tried one other spot and they had both. Opted to try 4831 next. We'll see. Only thing is that the max load is also a compressed load which I'm not to sure about.

[mistered]

raf said:

That shot would have had me scratching my head if the rest had been close, but they weren't. I know I didn't pull it so shooter error is out. All I can think of is the rifle doesn't like that powder. I have a couple of others I want to try and my first stop, shopping, wasn't good. Didn't have either in stock and don't know when they'll get any. Tried one other spot and they had both. Opted to try 4831 next. We'll see. Only thing is that the max load is also a compressed load which I'm not to sure about.

A compressed powder charge isn't anything to worry about as long as it is arrived at gradually. I trust you know the signs of high pressures.
I would venture to guess that your groups opened up mostly due to copper fouling. Some rifles like a little copper in the bore and some don't like any. Some rifles (I think your .300 WSM included) shoot great up to a point and then accuracy falls off rapidly. It isn't any quick and easy thing to remove copper but the strong copper removers work pretty well. Do the drill as described on the bottle over and over until the patches come out without any cobalt blue coloring. Cobalt blue on the patch is disolved copper.
Have fun. Wish I had me one of them there .300s!
-Ed

[RAF]

I've used copper removers before, especially with 22-250 which is pron to copper fouling and really affects accuracy. I have some and used it the other day when I cleaned the rifle. Not much sign of copper. I think this rifle doesn't like this powder. I also checked the scope mounts and all seems tight. I've already made new bullets with IMR 4831 and have to wait for the weather to get back out and try them.

[mistered]

Raf- Wish I had me one of them there .300s with a bore so slick it don't pick up any copper. Hang on to that baby, Raf. Its a rare one.
-Ed

[RAF]

I didn's say there wasn't any copper there, just not what I expected considering the number of shots I fired. None of my center fire rifles pick up as much copper as my 22-250. Of course none of these rifles push bullets near as fast at the little rifle.

[antleraddiction]

Thats a big swing in POI and honestly can't say why if shooter error or scope is out the window!! Though it sounds as though all test loads didn't fair to well so a component(s) change is required. Which you have already done one switch! A little slowing burn rate powder should help your velocity with the larger volume charges allowed in the 300, whether accuracy improves time will tell. If you find some promise try tinkering with the seating depth, IB's are a little finnicky in regards to jump. My rifle likes .010 but have seen others that like to be seated further out better. Best of luck.

As to a compressed load, like mentioned if you arrive at safely then give it no more thought. I try to pick powder/load that have as little slosh in the case as possible (while still remianing safe), aka high load density. With the wsm high density and compressed loads are part and parcel(especially with slower burning powders).

What copper removing agent are you using? Are you using a bronze brush? I use sweets 7.62(next to impossible to find here locally anymore) or the other readily available is Barnes CR10. Wipe out foam is another but pricey, a little messy and slower. Shooters choice MC#7 is my powder,etc solvent of choice but does very little in regards to copper remover.

PS glad to hear your SIMS pad worked out for you in fit and function! I installed one on my savage 10II this off season and while the 4759 loads aren't worthy it will make multiple rifle sessions nicer(as is the case with the savage and cooling time) plus i plan to try some stouter loads with 300class bullets.

[RAF]

Lots to reply to here. First off seating depth. I played with the seating depth for quite a while to get it to .010. When I figured I had it, low and behold the Tikka magazine is to short. I ended up seating them so the bullets just fit, a long way from .010.
I checked the scope mounts and everything is tight. Hope it isn't the scope itself. I put my 6 - 24 Bausch and Lomb on it temporarily just to work up a load. That's my varmint scope. Next time out I'll run a few factory loads through it again to confirm it's shoot good.
The IMR won't need a compressed load. Before I said that, I only glanced at my manual, saw 4831 with a compressed load. Next time I checked it's H4381 that calls for a compressed load.
I use a barnes copper solvent and works good. Used to use Shooters choice but haven't seen it for a while. I heard about a foam one and should go have another look.
The limb saver works great and should is just fine after over 50 shots. But that heavy recoil did give me a head ache.