i went from lapua cases to remington cases and at the same time from a old batch of vit 560 powder to a new one and iam not getting the usual tight groups.i know its not the rifle as i still have some old rounds left and it shoots them in the same hole at 200.the new rds are really spread out for my tastes(4 inches).The powder charge in the rem cases is compressed due to the lower volume compared to lapua.I will eventually find the problem but was wondering if a more experienced reloader can recognize it beforehand.

You're on the right track suspecting internal volume. I believe there are several other variables not easily seen: -flash hole diameter -case neck tension -inconsistent case neck diameter -reloading die induced run out.

I also had some rust develop in my wilson dies and neck sizeing bushing,but the round seems concentric by looking at it.

You simply may be noticing the poorer quality of the Remington brass. Flashholes may be whacky, the bodies and necks may not be concentric. All sorts of brass abnormalities can affect the bottom line.

More expensive brass isn't always better but in this case you are working with two brands that are generally at the opposite ends of the spectrum in terms of pure quality. If you're not into sorting and prepping, I'd just buy the Lapua and be done.

Gabe

thanks for the replies,has anyone had such a difference in accuracy due to a case?

quote:

Originally posted by shootaway:
....The powder charge in the rem cases is compressed due to the lower volume compared to lapua....

A compressed load of vith. 560? IMO you are possibly exceeding the pressure limits; which bullets and primers are you using?

What I mean by compressed is that the bullet compacts and crunches down the powder when seated.This does not happen in the Lapua cases.I am useing federal large rifle magnum primers and barnes 180gr molly coated tsx bullets.I get accurate loads with 76,77 and 78gr of powder.Velocities are from 2980 to 3146 withno signs of high pressure.Again,the round is not accurate with remington cases and the new lot of vit 560.There is also some rust that has formed on the die,but do not think it has effected concentricity.

Why would you trade your good brass for lousy brass?

quote:

Originally posted by shootaway:
What I mean by compressed is that the bullet compacts and crunches down the powder when seated.This does not happen in the Lapua cases.I am useing federal large rifle magnum primers and barnes 180gr molly coated tsx bullets.I get accurate loads with 76,77 and 78gr of powder.Velocities are from 2980 to 3146 withno signs of high pressure.Again,the round is not accurate with remington cases and the new lot of vit 560.There is also some rust that has formed on the die,but do not think it has effected concentricity.

I do blame the brass in this situation, but I also think there are some other issues compounding your troubles.
First is the decreased case volume responsible for raising pressure. It is compounded in my opinion by the longer than normal Barnes monolithic bullet.
Secondly I would at the minimum clean & polish my die. When I refered to concentricity, I had a few .001" in mind -something that isn't noticable with the naked eye. Also, with heavily compressed loads and cases with weak neck tension, it is almost impossible to maintain a consistent O.A.L., thus accuracy is out the proverbial window.
Last, I would consider the powder variables, but in my experience V-V powders are about the best out there. I've used N-160 for more than a decade and have had no issues with consistency, sensitivity, or quality.
With that said, I'd scrap the brass before I put $100 into neck turning equipment

thanks buckshot

loaded some rds for this weeks shooting and noticed slight compression even with the Lapua cases.There is no compression once the fireformed cases are used.I don't know if compression effects accuracy.I am really looking forward to finding the problem.It will make me feel as if advanced in the reloading department.

Sako mod 2700 in 300wm rem or win brass never had any problems with these brands of brass using imr 4831,rem 9 1/2 or fed 215 primers with 165gr & 180gr nos solid base,nos 180gr accubond, 180gr sierra game kings or 220gr nos partitions very accurate loads.Load data from Nosler Reloading Guide 5th edition.

i like the barnes bullets,and want a super accurate load with a lowest pressure.it may be that the barnes are compressing the vit 560 powder in the new cases or in the new rem cases and the cases must be shot once to be really accurate.

So,here is what seems to be the problem.The rifle did not like the Remington cases and group size was halved by useing the Lapua cases.Then the groups with the Lapua cases were halved when I used the fireformed cases.It seems that when shooting hot magnum loads everything is more critical.Perhaps the Remington cases shoot better in Remington rifles.

RL22 is the powder for the 300 win mag. You can use a little less powder and still get the velocity. Make sure and start lower around 74 gr and work up to around 75.5 to 76 gr.

quote:

Originally posted by woods:
RL22 is the powder for the 300 win mag. You can use a little less powder and still get the velocity. Make sure and start lower around 74 gr and work up to around 75.5 to 76 gr.

Ditto that. I just ran some trials with varying RL22 powder charges and it's hard to pick which charge for further investigation because of the uniform group sizes.

Best thing to do is try them all and find out which works best in your case.Alot of factors to consider.