Home Forums Reloading Big Game Rifles When to try a different primer?

I can't say that I've had any changes in accuracy by screwing around with primers. I only use Federal 210's and 215's in my 300 WM. In my 06 I use 57 grns of IMR-4350 with 165 grn Nosler BT's. I only have the Nosler's just kissing the lands on all my handloads. I have to say that I'm with mathman here and that something else is going on besides the primer choice. This also might be the first time I've heard a complaint about a Cooper not shooting. Don't rule out a scope being bad as I've seen brand new scopes that were bad right out of the gate.

I usually don't mess with primers much either but every rifle is unique.

No my 1 and only Cooper gave me issues. I sent it back to Cooper not once but twice! I was so impressed with their customer service that I will be purchasing another down the road so glad that they are willing to back their product!

I had tried several different combinations with the Cooper and discovered that it needed 4-6 fouling shots before it "settled" for the nice neat groups. I don't clean it now until I have 40-50 shots down the tube and that is a "light"cleaning at that.

I duplicated the SMK load they sent using a 130 Speer BTSP and IMR 4064 for the 7mm-08.

I then decided I "needed" a 140 grain bullet to shoot and took a Barnes TTSX. The IMR 4064 that was shooting the 130's into bugholes at 100 yards was shooting 1.5-2.0 inches at 100 with the 140 TTSX. I tried several powders and decided to try H414 on a whim with the 140 TTSX, and I was .5 or less at max powder charge with the H414! I was a happy reloader but to get there was quite frustrating.

There are sorts of possibilities:

I have experienced drastically different results by changing primers, but so far only with spherical powders.

It is possible for both scopes to be bad, and scopes are always among my first suspects with accuracy problems. A guy on the Campfire was having terrible luck with, as I recall, 165's and H4350, and I suggested changing the scope, which was brand new. He resisted, because it was brand now, but eventually caved and tried another scope. The results were equally bad. A few weeks later he e-mailed me and said he'd tried a THIRD scope and the rifle started shooting under 3/4"!

Most of today's slower-burning rifle powders shoot better at maximum pressures, or even slightly over listed max. Every powder is designed to burn best within a certain pressure range.

If the brass has been previously fired, and the number of firings differs, then neck tension will vary and accuracy can as well.

I've seen dramatic differences with stick powders as well. In one instance my .338 was shooting 1" groups with H4350 and WMRP primers. One day I grabbed the Fed 215's instead, and my groups opened up to 3". Once I switched back, groups returned to 1".

So, they can make a difference.

snuzem, what primers are you currently using with the 4350?

Would have to agree. Ran into a similar situation with some 8208.

Good to know abt the 8208.

What's your been liking?

I've seen primers make a difference as Mule Deer mentioned with spherical powders and aside from that changing primers has always netted minor differences for me.

As Mule Deer stated I'd start by changing both scopes and it wouldn't surprise me a bit if its the culprit on at least one of the rifles.

I'm definitely suspect that there's more going on than every load you've tried was a terrible combination.

Shod

RDFinn, I agree with you about not hearing of a Cooper not shooting. My Cooper 54 in 7-08 shoots really well. I had another 52 in 30-06 that shot really well but a friend of mine wanted it really badly so I sold it to him( shouldn't have done that). I'll be changing the scope on the Cooper Before I go back to the range. Wil post results.
Thanks for everyone's input
Scott

I switch primers as part of my normal routine.

My Cooper 30-06 shoots best with 165-168 bullets and 4064, and acceptably with just about everything else. Acceptably wasn't 1/2" but it is a hunting rifle.

A few things to check that won't cost anything. Check the parallax in both scopes with the ole head bob test. If you've got roaming crosshairs anything you do is a waste of time. In some cases (Leupold mostly) you're better off working up loads at 200 than 100. The scopes are often closer to parallax free at 200.

I've got two Cooper rifles and both had an extractor that pressed against the inside of the receiver ring when there was a case/cartridge in the chamber and it was worse as pressure went up. It just about drove me crazy because I would just be getting the pressure up high enough to shoot and the bolt would start binding in the receiver, acting like high pressure when old proven loads and the chronograph said otherwise. The bolt handle would lift normally, but pulling it back took a good tug to get it moving. That one took longer to spot than it should have, but nobodys perfect. The quick check is to mark the outside of the extractor with a sharpy and fire a few rounds. If its dragging that's your problem. If it isn't it never cost you anything to check.

Many scopes have a degree of reticle float. It may not be "broken" by many people's standards but you'll never get 1/2 MOA out of a 1 1/4 scope except by fluke. If you got a very accurate varmint rifle pull the scope off it and use that for a test control.