Rem 7.5 primers not fully seating in Lapua 221 cases. Anybody else?

[VaniB]

Handloaded for my Remington 700 LVSF 221 Fireball with BR4, WSR, CCI400, and Rem 7 1/2. Went to the range today and couldn't get a third of the cartridges with the 7 1/2 primers to chamber, while the other brand primers chambered fine.

I noticed when I was priming the new Lapua cases with the 7 1/2's that the primers wouldn't seat all the way in. I had to ram them hard or ram them numerous times to get them unstuck from the shell holder. Upon close examination, I was able to see the anvils of the primers protruding a little beyond the edge of the primer. I didn't think much of it, because I have used this same lot of primers on my AR15's without issues at the range.

Anybody ever experienced this?

 

[fyrewall]

Almost all primers have the anvils protruding beyond the edge of the primer to some degree with some exceptions of minor or no anvil protrusions for some mil-spec primers intended for semi auto guns, these would include CCI 41's. My suggestion would be to measure and then compare primer dimensions with the ones that did fit easily with ones that did not. Another consideration would be primer diameter. My experience with 6.5X47 Lapua brass and Rem 7 1/2's is that they take some force to seat in new brass using my cheap Lee, press mounted primer seater that can produce large seating forces. My guess is that your Lapua brass has tighter primer pockets than that of your AR15 brass, most likely .223.

My suggestions would include not smashing or squashing primers during the primer seating process. Rem 7 1/2's are my primer of choice for 6.5X47 Lapua. Measuring them with the tail of my caliper shows the Rem 7 1/2's to be .003 under surface of brass.

 

[Webster]

Handloaded for my Remington 700 LVSF 221 Fireball with BR4, WSR, CCI400, and Rem 7 1/2. Went to the range today and couldn't get a third of the cartridges with the 7 1/2 primers to chamber, while the other brand primers chambered fine.

I noticed when I was priming the new Lapua cases with the 7 1/2's that the primers wouldn't seat all the way in. I had to ram them hard or ram them numerous times to get them unstuck from the shell holder. Upon close examination, I was able to see the anvils of the primers protruding a little beyond the edge of the primer. I didn't think much of it, because I have used this same lot of primers on my AR15's without issues at the range.

Anybody ever experienced this?

Buy a primer pocket uniformer.

 

[hunter67]

Or don't use those primers

 

[Coyotefurharvester]

Have some Nosler 22-250 once fired to reload, primed with Rem. Tried the first couple in the rifle with the firing pin removed, tight bolt closing,wth. Checked loaded round with comparator, it's .0025+. Ding,ding,ding check primer,pulled round apart. Primer pocket fine for CCI or Win primers, but .004+ shallow for the Rem primers. Had to buy a uniformer.

 

[VaniB]

Ahhhh....yes. A pocket uniformer! I've got one! Thanks for the reminder.

I had gotten out of the sport of precision rifle shooting for about the last 5 years, and probably hadn't used it for over 10 years when I had last handloaded for my 22x47L. The tool had since mainly been assigned for cleaning the pockets out of my fired pistol brass. (Though I avoid that too, so as not to dull the blades on the grimy carbon)

 

[Dusty Stevens]

Ahhhh....yes. A pocket uniformer! I've got one! Thanks for the reminder.

I had gotten out of the sport of precision rifle shooting for about the last 5 years, and probably hadn't used it for over 10 years when I had last handloaded for my 22x47L. The tool had since mainly been assigned for cleaning the pockets out of my fired pistol brass. (Though I avoid that too, so as not to dull the blades on the grimy carbon)

Just use it. Itll grind the carbon out as well as uniform the pockets. 112yrs from now, if you shoot a lot and the next few owners shoot alot, the blades may get dull

 

[hemi]

I had a similar issue with Lapua 221 brass converted to 20 Vartarg. My problem turned out to be "operator error" (me). First time neck turning brass, I ran a few cases over an expander in preparation to neck turn and turned those cases. When seating the first primer they would not seat nearly deep enough. I looked at the next primer pocket in line and noticed the flash hole looked a tad large.....hmmm....Backtracking my operations I noticed the tapered tip of the expander mandrel in the expander die had a bit of brass on it. The light bulb went off! The 221 case is so short the mandrel tip was adjusted too deep and I actually pushed into the flash hole and not only opened it up a bit, but also pushed the web down making the primer pocket shallower.
At the time I was actually kind of proud of myself for figuring out what had occurred because my initial reaction was to blame the brass for being defective. Thankfully I only ruined less than 10 cases and learned a valuable lesson.
hemi

 

[VaniB]

Or don't use those primers

Looks like using another primer is going to be my only solution.

Tonight I used my primer pocket uniformer, and the problem persisted. I measured the 4 different small rifle primers I had on hand and got the following measurements with the Remington confirmed as being the tallest;

Rem 7 1/2 @ .122"
BR4 @ .120"
CCI400 @ .119 1/2" (ie; .1195")
WSR @ .115 1/2" (ie; .1155")

 

[hunter67]

Thats interesting. I will see what Im loading my 20vt with. You have my attention

 

[grovey]

CCI 400's are my go to for the fireball.

 

[fyrewall]

The Rem 7 1/2's have always easily seated for me in Lapua 6.5X47 and Remington .223 brass.

I encountered a problem with seating Federal AR match primers in Hornady brand .204 Ruger cases. The problem was caused by a an abrupt 90* edge of the top of the Hornady primer pocket just at brass level that got hung up on the square sharp bottom edge of the Federal AR match primers . Examination of both primers under my B&L 10X Hastings triplet showed the bottom of the CCI 450 primer to have a 45* bevel and the bottom of the Federal ARM primer to be a sharp 90*. The Hornady cases had correct depth primer pockets and when the top of the primer pockets of the Hornady brass were beveled to 45* the Federal primers seated with permissible force. I see the same abrupt 90* form on the bottom of the Remington 7 1/2 primers as found on the Federal AR match primers.

I used my B&L 10X Hastings triplet magnifier on the job for years to look at tiny details and now I keep it in my desk drawer next to my loading bench and it sees use every day. It is 60 years old; B&L still makes them and they are available on line for about $30.

Yes, switching primers probably would be the best solution.

 

[hunter67]

I am using 7.5 in my 20vt. Maybe it is a lot issue

 

[232]

You could also use different brass

 

[fyrewall]

Here are some photos of a CCI 450 (nickel plate, top) and a Rem 7 1/2 (brass, bottom)

I can see a very small bevel on the CCI 450, apparently this is enough to prevent the edge of the primer from hanging up on the top edge corner of the primer pocket. It sure looks tiny. If it were round it would be a "radius" I can also see that the anvil legs are beveled. This primer can be easily seated into any small primer brass.

The Remington 7 1/2 looks like it has an abrupt 90* corner. This is the same as my Federal AR Match primers that needed to be carefully guided into primer pockets that I had beveled the top of the primer pocket.

Anvil protrusion appears to be a tiny bit less on the 7 1/2.

 

[VaniB]

I measured 3 different lots of Rem 7 1/2 primers I have, and they were all the same height. (except 1 lot was a single 1,000"th shorter.) These same primers seated fine in my Lapua 20Tac cartridges too. This Lapua 221 Fireball brass I have is probably partly to blame being tight toleranced.

Thanks for all the input guys. I dragged my arse to the garage to experiment with chucking my 1" tall RCBS uniformer bit into my power drill. I then firmly held the mouth of the Lapua case down against the work bench to keep it from spinning in my fingers, and drilled down firmly into the pockets. It took me all of about 5 seconds to do each case. Believe it or not, some of the cases will still not stand completely square and flat on my table top with a Rem primer in it. BUT, it's a vast improvement, and all the cases feed into the rifle now.

I have never had to study primers like this before. Thanks to your help, I now understand how the beveled or 90° edges of a primer can cause different results. Consider it's tall height, and if the Lapua pocker has tight tolerances, and it's not such a mystery any longer.