SmallCaliberCentral

i ran out of my remington 7 1/2 primers and they are older and they were marked magnum .
i go today and tell the nice man at the gun shop that i would like some 7 1/2 magnum primers and he hands me 7 1/2 bench rest . i look at him and asked if they don't have small rifle remington magnum primers . he said all Rem ington 7 1/2 are BR . now granted my old box of 7 1/2 ''magnums '' are about a + twenty yrs old , did they change something on me since i bought mine ? is it the same primer ?

The only 7-1/2 primer I'm aware of, and have used for over 30 years, is the 7-1/2 BR primer. I've never seen any marked "magnum", as the BR guys usually use cases with around 30 - 35 grain case capacity, and you sure don't need a magnum primer to ignite that much powder, ball, spherical, extruded, whatever.

If you have a box of 7-1/2 BR "Magnum", it will be the first one I've ever encountered.

not 7 1/2 BR Magnum , you are correct , it says br only .

edit ; i just went down and dug out some old reloading notes and the primer box . i made a note and where i got the info from is hard to tell back then . but my notes say that this primer has the burn rate of a magnum primer and to use with ball powders . where i got this info from back in early 70's i have no idea . it could have been the NRA magazine in that time era . but for some reason i was under the impression that a remington 7 1/2 primer was a magnum strength and i was looking for that on the box to say 7 1/2 magnum . thanks for steering me straight .

Ran this test with a 204 a couple years ago:


27.8 gr H4895
32 gr VMax
2.250 OAL
Winchester Brass (new)

205M

3970
3983
3995
3979
4012

3987.8
14.52446212
210.96


205

3926
3976
3975
3935
3954

3953.2
20.33125672
413.36

BenchRest

3928
3950
3984
3975
4008

3969
27.65501763
764.8

Win

4043
3983
3989
4048
4002

4013
27.28369476
744.4

400 CCI

3946
3939
3959
3963
3954

3952.2
8.704022059
75.76

41

4085
4071
4082
4053
4040

4066.2
17.24412944
297.36

CCI 450

3903
3944
3963
3939
3913

3932.4
21.70345595
471.04

Rem 7.5

4051
3897
3931
3944
3928

3950.2
52.70825362
2778.16

You aren't dreaming, the old Remington 7-1/2 primers were the magnum small rifle primer from Remington with the 6-1/2 being the standard small rifle primer. An old Lyman reloading manual from the 1960's states that the .223 Remington loads were developed using Remington's new 7-1/2 primer. That primer was developed expressly for the .223 Remington (or 5.56x45 NATO) running in the AR-15. I recall using quite a few back in the '60 and '70's. Then they dropped the Magnum designation calling it the 7-1/2. Then they offered a 7-1/2 BR primer and eventually dropped the 7-1/2 name. They were designed to ignite ball powders with a heavy deterrent coating, and have a heavier cup to withstand the pressure and slamming around of semi-auto and auto cycling. Loads that would pin-hole or blank a 6-1/2, or smuge a Federal 205, wouldn't even flatten a 7-1/2.

The other change was in manufacturing all Remington primers. Previously all Remington primers had a two legged anvil, with twin flash holes. Then at some point they switched to the three legged anvil that is the industry standard. I just went back in my supply and found one box of Remington 9-1/2 Magnum Large Rifle primers that have the two legged anvil, while a newer lot has the three legs. I dearly loved those two legged primers, because in all loads they gave the best accuracy. Maybe it was because the anvil is more rigid or the flame delivered more consistently, maybe it was just because my confidence was higher that they shot better. Then maybe they're not made by Remington anymore, who knows? All I know is that the 7-1/2 BR seems to deliver the best accuracy in many rifles, especially with ball powder, which is why I'm down to my last 12,000 and looking for more.

acloco, Thanks for the test data. That is something I always to do. I was surprised the CCI 400 preformed better than the 205M's.

thank you wrangler john , and if you have that old lyman book around check out the loads for a 75 gr bullet in 25-06 using 4064 and compare it to a newer sierra book . i'm going by memory only , i used to use that book back in the late sixties , i think those loads back in that book were more liberal in some loads than the current books . wish i would have kept that lyman book .
also want to thank acloco for posting your reference material , found it quite interesting . also wanted to know if any of the ''thinner'' primers had any signs or problems with puncturing or any other pressure indications that i have read about with the 204 while doing your testing ?
thanks gentlemen , dan

doobie: The Rem 6-1/2 is designated for the Hornet and similar lower pressure cartridges. It makes sense now since W. John posted that the old lots of 7-1/2 were actually called 'magnum' primers back when they first appeared. The 6-1/2 is much more mild, has a thinner cup as noted, and gives stellar performance in all Hornet-based cases.

Wrangler John, thanks for posting that info.

Rick in Oregon wrote:doobie: The Rem 6-1/2 is designated for the Hornet and similar lower pressure cartridges. It makes sense now since W. John posted that the old lots of 7-1/2 were actually called 'magnum' primers back when they first appeared. The 6-1/2 is much more mild, has a thinner cup as noted, and gives stellar performance in all Hornet-based cases.

Wrangler John, thanks for posting that info.

Not that I would EVER suggest doing this....but Rem 6 1/2's also work perfectly in my Springfield XD in 40 S & W as pistol primers as well.

Guys, I've been doing some more research on the subject of Remington 7-1/2 primers. From what I can reconstruct they were labeled "Magnum" not because the priming mixture was "hotter" but because they had a stronger cup to withstand the rigors of being used in high pressure loads commencing with the .223 Remington and .222 Remington Magnum, and in auto loading applications. In other words they weren't magnum primers because of the priming mixture but because they were for magnum loads. I finally found a chart in the old Lyman manual that listed the Remington 6-1/2 and 7-1/2 in the same chart cell for standard small rifle primers. Apparently the priming mixture was hot enough as it was.

From the manual, referring to the 7-1/2: "Designed for use with 221 Rem., 222 Rem., 222 Rem. Mag. & 223 Rem. cases. Contains a harder cup to prevent cratering with these hotter cartridges."

I do recall for a while they were labeled simply 7-1/2 while the 7-1/2 BR were also available. Whether this was due to stocks of 7-1/2 being available at the same time as the 7-1/2 BR which replaced them is unclear. What is clear is that the 7-1/2 BR is a consistent primer that gives superior results in some cartridges and rifles. CCI produced a true small rifle magnum primer as listed in the chart, with CCI now listing four separate small rifle primers. The only other true small rifle magnum primer commonly available is the Russian Wolf brand.

Doobie: This manual is too old to list the .25-06 which wasn't a factory round when they published it. It lists the 250/3000 Savage, .257 Roberts, and .257 Weatherby Magnum as the only modern .25 calibers. Remington adopted and developed SAAMI specs. for it in 1969 and this manual issued from around 1966-'68. I always use caution when using historical load data. Powders have changed over the years, some being made off shore now, or were originally surplus lots. When using Ackley's old data I back off quite a bit and start over, because Ackley was known to push the envelope, and that envelope is 4350 or 416R steel right in front of my face, and I am such a handsome fellow!

Do your homework on the REM 7 1/2 primer......It's origins go back to when the 17 remington was developed. The primer was designed just for that cartridge at the time.

This info comes directly from one of the best gun writers on planet earth.

FB Guy: Don't keep us in suspense.....who then, is this writer?

.....

Layne Simpson.