Which Primer for my .300 Win Mag Load?

[BigSky112]

I use only Mag primers in my (2) 300 Win Mags. I currently use CCI but have used Federal, did not see any difference. CCI is what is available now in our area. gun)

 

[WYcoyote]

Because I can be hunting in cold weather I use a magnum primer, Federal GM 215 M and I use the match version so I sleep better at night.

 

[DocB]

the wlr is a heck of a primer for middle sized rounds where you don't want to go with a 215, 250 or wlrm. Remember though, the wlr isn't that mild of a primer as win designed it to light their Ball powder up in standard casings.

Ok Lefty, I've just about got everything gathered up to start my loads for my 300WM (24" barrel). Going to go with 215gr hybrids and 208gr Amax's, WW brass, and work up separate loads for IMR 7828ssc and Retumbo. (can't find H1000 in my AO). I've found WLR and WLRM primers, the price is not much difference. Question is... will WLR be up to the task or should I just go WLRM, which is where I'm leaning towards.

Thanks Sir!

DocB

 

[tbrice23]

Personally I'd use WLRM.


Hodgdon manual uses win.LR (hope its not a typo in their manual!) You will probably find a good load with either BUT it will be with a different powder charge with different primers so work up slowly if you switch.

 

[johnnyk]

The Fed 215 is a bit hotter primer than the CCI 250 but either will do fine AS LONG AS YOU ARE STARTING LOW AND WORKING UP WITH THE POWDER. This is also true with using mag primers in smaller cases. Most ball powders recommend using mag primers. My pet 25-06 deer load uses CCI 250 with IMR 4350.

I totally agree with this and have used magnum primers in .22-250, .243 and .25-06 in years past. Work up and see what you get. You may just get the best load your rifle has ever produced.

I used H1000 and CCI250 with the 185gn Berger and got good accuracy (.4305") @ 79.5gn. ES and SD was also low (13.46 & 7.00, respectively) with this charge. Velocity was meager (IMO) at 3095fps, but should be easy on barrel and brass.
I started at 79.0 and went to 80.5gn, but accuracy was unacceptable to me (1.017") at the higher end. Velocity was real good at 3148fps.
Either way, start low and work up. H1000 w/CCI250's is an excellent combo in my .300WM. Happy shooting. JohnnyK.

 

[FEENIX]

the wlr is a heck of a primer for middle sized rounds where you don't want to go with a 215, 250 or wlrm. Remember though, the wlr isn't that mild of a primer as win designed it to light their Ball powder up in standard casings.

+1! Scanned this off my Lyman reloading handbook (49th ed) pg 57.

 

[tbrice23]

Very surprising that cci200 tested hotter than f210m. And again is the formula the same today as when the test was observed?

 

[FEENIX]

Very surprising that cci200 tested hotter than f210m. And again is the formula the same today as when the test was observed?

That's why I provided the source reference as that would be the baseline. lightbulb

 

[Lefty7mmstw]

Ok Lefty, I've just about got everything gathered up to start my loads for my 300WM (24" barrel). Going to go with 215gr hybrids and 208gr Amax's, WW brass, and work up separate loads for IMR 7828ssc and Retumbo. (can't find H1000 in my AO). I've found WLR and WLRM primers, the price is not much difference. Question is... will WLR be up to the task or should I just go WLRM, which is where I'm leaning towards.

Thanks Sir!

DocB

It depends on your minimum temperature encountered. If you don't get much below freezing, a wlr should be enough in a 300 win with stick powders. If you are going to get to sub-zero temps. though, I'd go with a mag. primer any day of the week and twice on Sunday.
Sometimes milder ignition will help load uniformity a bit, but you risk the fire not being hot enough in really cold temps in the larger cases, especially when you are using slower powders with a lot of deterrent coating on them.

 

[DocB]

It depends on your minimum temperature encountered. If you don't get much below freezing, a wlr should be enough in a 300 win with stick powders. If you are going to get to sub-zero temps. though, I'd go with a mag. primer any day of the week and twice on Sunday.
Sometimes milder ignition will help load uniformity a bit, but you risk the fire not being hot enough in really cold temps in the larger cases, especially when you are using slower powders with a lot of deterrent coating on them.

Thanks Lefty, temps here in VA are rarely below zero, but when I move to Wyoming or Colorado, they will get there! lol. I'll be working up my loads again after we move.

I think that I'll work up loads with both primers and both powders now that they're available and see which is the most consistent and accurate, then take it from there.

Thanks for the help!

DocB

 

[reeldawg]

I have Rem 700 300 Win Mag and shoot 215 Bergers. I tried 210Ms and 215Ms. Mine liked the 210m better. I don't have to worry about extreme cold in Florida. I read a couple reports about the new Marine Corp 300 Win Mag load and they are using 210Ms. I would try them both.

Jay

 

[Pdvdh]

This chart caused me to measure the cup diameter of all the large rifle primers currently available in my reloading room.

My measurements show less difference:

Large Rifle Primer Cup Diameters
Federal GM210M _ _ 0.21025"
Federal GM215M _ _ 0.2105"
CCI 200 (20yr old) _ 0.2105"
CCI 250 (35yr old) _ 0.2095"
CCI 250 (2yr old) _ _0.2105"
Winchester WLRM _ 0.2100"

Conclusion. Measure your primer diameters if really need to know.

The smallest diameter primer I measured was from a box of 35 yr old CCI 250s @ 0.2095". A current CCI 250 measured 1 thou larger at 0.2105"

All the rest were close to the same - within 0.0005".

 

[Wisner74]

My Dad gave me a box of 1000 WLRM. I don't see much talk about these on here. Would be using them for 300 Win Mag. Any advise for this??

 

[DocB]

My Dad gave me a box of 1000 WLRM. I don't see much talk about these on here. Would be using them for 300 Win Mag. Any advise for this??

I would tell your Dad "Thanks Dad", give him a big hug and ask him "Got any more?"

Load 'em up! They work just fine.

DocB