I am shooting a Weatherby Vanguard 7mmRM. Some groups are 1"-1.5" and some are .375" in size. Have used Barnes,Nosler,Hornady,Berger bullets. Powder is IMR4831 and Reloader 22. The primer is Fed.215M. I was talking with a person about this wide spread of my group. He thinks that the 215M primer is to hot for my 7mmRM. He said I need to use a Fed.210m primer.
The rifle has the barrel floated and the action bedded. 1.5 pound trigger pull. Bell and Carlson stock.
Any ideals?????
THANKS Jerry

My Sierra manual calls for a Fed 215 which is the magnum primer which would be appropriate for the slow powders you are using. The primer is not too hot. A Winchester magnum primer is hotter than others so don't try that one. The M is for match. The standard large primer for Federeal is the 210. Sounds as though you have done the right stuff to the rifle to make it accurate. You can play around with the seating depth and bullet weight also. Pick your favorite bullet and then start working out the bugs and you will save a lot of time and headache.

I use the large rifle primers (CCI 200) in my 7mm Rem. Mag. as opposed to the large rifle magnum primers. If you don't like your results with the Fed. 215Ms by all means try the 210Ms. I also like RL-22 for the 7mm Rem. Mag.

I'm not sure the match primers are significantly better than regular primers but I frequently use them anyway; superstition I guess.

What reloading manuals are you using and what primers do they use for the 7mm Remington Mag? Primers make a tremdous difference in pressure, and if you're unsure, then it can't hurt to stay with the manual's choice.

Jaywalker

In my experience (and I've actually tried this in a number of cartridges), different primers even magnum vs regular primers in cases the size of the 308 Win. and larger gives no noticible difference in pressure. In my experience, the only time I found a noticible difference was in some 44 Rem. Mag. loads I was testing.

I would agree though, if you're not experienced or confident in doing this sort of thing, don't do it.

Let's see... Reloading manuals... I have a couple from Hornady, 2 from Speer, a Lyman, a Hodgdon and a Barnes manual. Maybe there are 1 or 2 I forgot. I also subscribe to Handloader Magazine.

I use the 215 in my 7mm Mag and I use H4831 and H1000. For my 7mm Mag powders.

At 200yds my group is right around 1" to 1 1/2"

quote:

Grumulkin: In my experience (and I've actually tried this in a number of cartridges), different primers even magnum vs regular primers in cases the size of the 308 Win. and larger gives no noticible difference in pressure.

That's odd, as most recent strain gauge pressure tests show significant variances, particularly when compared to older methods, such as LUP and CUP. They find that while overall pressure doesn't change much, hotter primers, i.e., magnum primers, may cause 5,000 to 10,000 "spikes." Older methods, or even observations of cases for overt pressure signs, don't show these variances. Doesn't mean it's true in all cases, though - can you describe the tests you've run?

Jaywalker

There was a recent article in "Handloader " about different primers. They do make a difference.

Years ago I did a little experiment myself with the same load in the same rifle and just changed the primers. The groups varied by 150%. I didn't have a chrony or pressure gauges at the time.

quote:

Originally posted by jy:
I am shooting a Weatherby Vanguard 7mmRM. Some groups are 1"-1.5" and some are .375" in size. Have used Barnes,Nosler,Hornady,Berger bullets. Powder is IMR4831 and Reloader 22. The primer is Fed.215M. I was talking with a person about this wide spread of my group. He thinks that the 215M primer is to hot for my 7mmRM. He said I need to use a Fed.210m primer.
The rifle has the barrel floated and the action bedded. 1.5 pound trigger pull. Bell and Carlson stock.
Any ideals?????
THANKS Jerry

I have used both magnum and standard primers in the 7mm Rem. Mag., and frankly see no benefit to the magnum size. I now use the Fed. 215's ONLY in the .416 Rigby......

You might want to try a few other powders. My 7mmRM shoots best with IMR7828 with most bullet weights. H1000 was also good with the heavier bullets, 160 and 175gr.