I tried some Winchester Large Rifle Magnum primers in my 300 Win Mag today. They are very loose in the pocket. I have been shooting Federal 215's in the Winchester brass I'm using. They fit tight when I tried a few of them in the same brass. I think its been fired three times.

I tried the Winchester primers in some once fired Remington brass and they fit fine. Has anyone else had this problem? I'm assuming that the primer pockets enlarge because the case head is expanding.Should I discard the Winchester brass?

Pitch it !


Travis F.

I quit using winchester primers and only use federal now in my rifles for that same reason.

Are the primers slightly different in size? Is it dangerous to use brass with enlarged primer pockets?

I've used some brass with very loose primers,
telling myself "just one more go". Didn't seem
to affect anything. I have heard they tend to
leak and burn a ring around the fireing pin on the bolt face. Guess what I have on my bolt face?
John L.

Remember the function of a primer: it serves as a spark and seal. If the primer is fitting loosely, it will not seal the cartridge case well. This may cause variation in velocity due to escaping gas (hence that ring around trhe firing pin hole).

If you have primers that seems to fit tightly, I would use those primers and reserve the winchesters for another set of brass.

Remember: when seating a primer there should be some resistance by the primer pocket.

If the primers are fitting loosely in general, it is time to throw the brass out regardless of the number of firings.

Consistently loose primer pockets with different manufacturers of brass suggests a load that is max or over max. and you might want to back the powder charge down alittle bit.

Gurrie

Elk Hunter,

I've had the same problem. The wins are not very snug for me even in once fired factory brass from time to time. I've found that the Feds are tight most every time. They are alittle wider. I've went to Federal Gold Metal Match for all of my Magnums except 300 WSM. I do use quiet a few of the WLR primers in all of my standard cal loads and they seem to work fine.

I have found that if you use federal 215s and then try to switch back to win LRMs in the same brass, they almost never fit.

Good Luck!

Reloader

FYI CCI mag primers are a bit on the big side and will often give you a good seal in cases with enlarged pockets.

I've been using win primers in new brass cause the slip in like butter. I believe they would fit loose if the pockets had any wear and tear. I think the win primers don't have the silver coating on them that other primer mfg's use. You might want to back that load down a little. If you find a brand that fits somewhat snugger I'd shoot the brass again. For sure--when a federal primer is loose it's time to toss....

elkhunter,

I use to use WW primers exclusively for all of my reloading. Several years ago I started to get WW primers that would slip into new brass too easily. I measured and found the new batch I bought was @.001 smaller than the previous batch. I quite using WW primers at that time.

At least in my experience, I have found variation in primer diameter. In loading virgin WW 300winmg brass I have found Rem mag primers to be very tight, (too tight for my liking). CCI to be just right and WW to go in just like butter as Kraky said, but a little too much on the lose side for my liking.

I have been using CCI exclusively and they seem to match the primer pocket on all WW brass very well.

Jim

Yep, WW primers tend to fit a little loosely and Federal primers tend to fit tighter than others. Like the headspace on a gun or the shoe on a foot, if it fits, wear it.

WW primers do well in new brass. One of the reasons that Federal 215's have been popular for "magnums" is that they fill out primer pockets expanded from excessive pressures enough for "one more go" (and let hotrodders believe that their favorite whiz-bang loads that are three grains over "book" are "just fine").

CCI, Remington, and RWS primers seem to me to be in the middle and in the same primer pockets will seat with a little more resistance than WW and a little easier than Federal. In fact, I quit using Feds years ago because they seemed to require excessive seating pressure in new brass (these were 215's; I actually think that they may be a tad larger than the 210's).

I use RWS 9.3x74R brass for a wildcat & the primer pockets are very tight w/ Fed. primers. Rem. primers fit great. There must be a very small diff. in primer diameter among brands.

When in doubt, whip out your micrometer!

I found WLR primers do not have the same "feel" as Fed or CCI's with my primer tool. Plus, when you REMOVE the WLR's they "pop" right out. Not a tight fit.
That's why I use FED and CCI's.

SAAMI specifications on primers and primer pockets per "Sinclair International's Precision Reloading & Shooting Handbook" 10th edition 1999

......................Depth min max diameter min max
small rifle primer pocket .117 .123 .1730 .1745
small pistol primer pocket .117 .123 .1730 .1745
Large rifle primer pocket .125 .132 .2085 .2100
Large pistol primer pocket .117 .123 .2085 .2100

.......................Height min max Diameter min max
Small rifle primers .115 .125 .1745 .1765
small pistol primers .115 .125 .1745 .1765
large rifle primers .123 .133 .2105 .2130
large pistol primers .115 .125 .2100 .2120"

What does it all mean?
Those large rifle primers should be at least .2105" in diamter, and the pockets in the brass should be no bigger than .2100".
So there should be at least .0005" of interference.

I had the same problem with win primers on my 300, some fit good others loose. I tossed the bad brass, but i should have tried another brand of primer. I use FED. for most but on the mad. I use Win. When they are gone I'll buy another brand..P

Just for interest, Long ago when I was reloading
12G target loads, I believe the normal primer
sold was a wisker larger than the factory
and then when they got loose, you could buy
some marked about 1thou. larger. (.245 by memory.)
JL