Reloading 243 Winchester

[larmar1942]

Having difficulty seating primers in 243 cartridges. Any tips? Thanks, Larry

 

[Mike SC Hunter]

get a primer pocket reamer.

 

[rockquarry]

Having difficulty seating primers in 243 cartridges. Any tips? Thanks, Larry

Never heard of such. Want kind of primers and brass? What kind of seating tool? You shouldn't need a reamer.

 

[rwsmith]

I use the Lee pocket reamer and a deburring tool chucked in my drill press to bevel difficult cases a little. And if there is going to be a problem that shouldn't exist, I'll find it.

 

[larmar1942]

Never heard of such. Want kind of primers and brass? What kind of seating tool? You shouldn't need a reamer.

Winchester primers, Starline brass, RCBS single stage

 

[toad67]

Weird, you shouldn't have any problems with that combo. Do they happen to be #41 primers by chance?

 

[gwpercle]

Are you seating the primers on / with the RCBS press ...
If so ... do you have the correct sized priming arm and cup installed on the seating arm .
I use Winchester WLR... Large Rifle primers .
Large Rifle seem to work just fine .
StarLine brass will have no crimped in primers to contend with ... so it's something else !

What are you using ?
Check your primer seating cup too .

Gary

 

[rockquarry]

Winchester primers, Starline brass, RCBS single stage

If it's not inconvenient, try some different brass and primers and see if the problem continues. I've never experienced or heard of Starline brass or Winchester primers being out of spec, but I guess it's possible.

 

[243winxb]

RCBS Ram Prime Unit. Seat all, even in short pockets.

Only seen some 38 spec brass that needed pockets reamed deeper.

 

[JimFr]

Having difficulty seating primers in 243 cartridges. Any tips? Thanks, Larry

I just bought the primer pocket "uniformer" by Sinclair.
I couldn't believe how much variation the pockets had . . . .in ALL the various brands of brass I have!
Even in the very-same LOTS of brass!
Finally, I have no "proud" primers on my ammo!

 

[rockquarry]

I just bought the primer pocket "uniformer" by Sinclair.
I couldn't believe how much variation the pockets had . . . .in ALL the various brands of brass I have!
Even in the very-same LOTS of brass!
Finally, I have no "proud" primers on my ammo!

I bought a Sinclair tool more than thirty years ago. Not long after, I uniformed a batch of 500 new Winchester .308 brass for cast bullet shooting. After all that work, I realized it had been nothing more than busy work but it hurt nothing. I haven't used the tool since. The brass was already pretty uniform as is came. Perhaps the quality of some brass has gone down, but I've been fortunate in finding no brass that had significant variation in primer pocket dimensions in sixty years of handloading.

 

[Crazywader]

Interesting - Starline brass is pretty darn good - very consistent in dimensions and weight. I've resized once-fired .308 cases (iirc - Lake City?) down to .243 just for the experience. Since it was military I knew the primer pockets would need work because of the crimp. Thought I'd made the mental note and moved on. A few years later I was reloading .308 once-fired Aguila brass for a buddy. Couldn't figure out why it was so hard to seat the primers even though I'd prepped the holes and cleaned the pockets. Turns out those were crimped. Lesson learned. Now, I go back and ream as soon as I experience more than usual resistance when seating. Maybe those pockets on the Starline are slightly out of spec?

 

[380shooter]

I just finished seating about 60 in my old Lyman Spar-T with no problems. Make sure that you have proper seating "plug" in you press. Some of the ones that came with my press and dies are rounded(concave) and don't seat properly. I wrapped them in lavender and old lace put them away never to use again. Just my experience.

 

[H Richard]

I always do my initial prep on new cases the 1st time. That includes primer pocket uniforming and flash hole de-burring. If necessary, also neck turning. I did 500 rounds of new Winchester .243 (for Prairie Dog shooting) a few years ago. It turned out very accurate out past 500 yards.

 

[larmar1942]

If it's not inconvenient, try some different brass and primers and see if the problem continues. I've never experienced or heard of Starline brass or Winchester primers being out of spec, but I guess it's possible.

I only have one size priming cup. Are there different sizes for different calibers?

 

[toad67]

I only have one size priming cup. Are there different sizes for different calibers?

There are two different sizes, one for small R/P primers, and one for large.

 

[larmar1942]

There are two different sizes, one for small R/P primers, and one for large.

Thanks, I think that will solver the problem.

 

[toad67]

Since your 243 uses LR primers, I doubt that you are using the small primer cup, LR primers wouldn't set flush in the cup and doubt that you'd be able to seat any primers.

 

[Dave Haynes]

I think that there are manufacturing tolerances involved at both ends, case and primer. I've had proud primers on 5.56 pre 80s cases and CCI SRP for a long time. Nothing helped to get them to seat all the way down. The #41s the same thing.