SPP vs LPP

[Walter Laich]

Switching to SPP for 45 ACP is fine, but what about 45 Colt and 44 Mag? I can't find LPP's anywhere in my area.

HSM Ammo is now reloading .45 COLT with SPP!!

I emailed them and had it confirmed

[Mk42gunner]

In my own personal opinion, .45 ACP should have been converted to small primers when the .38 Special was in the 1930's.

Robert

My understanding was that when Browning invented/developed the .45ACP,
he cut down (large primer) .30-06 brass to do it with. After that, it became one of those things where 'we've always done it that way' and use the LPP.

Except that the .45 ACP was brought out in 1905, he (or Colt) may have used .30-03 or even one of the Mauser cartridges as the basic brass.

I'm sure a lot of it was due to the military not wanting to change cartridge specifications for one cartridge, totally disregarding the fact that Frankford Arsenal had its own oddball sized primers. 0.204" IIRC.

I did a bit of research back when the spp .45 started showing up, and the .357 Magnum and the .45 have virtually the same useable case capacity. To me this means that the spp should be sufficient for both. I think I found the capacity info in one of the Lee manuals, not 100% certain.

It is kind of a moot point for me since I don't load or shoot much .45 anymore. and have pretty much a lifetime supply of lpp brass.

Robert

[cwtebay]

I find it interesting that I have a couple of early 1911 examples and a couple of WW2 era examples that treat SPP quite differently. The earliest one will strike almost half primer pocket, second oldest is slightly better - both strike the 11:30 position. The newer ones handle either with a center strike.
Neither seem to affect accuracy!

Sent from my Pixel 5 using Tapatalk

[firefly1957]

From what I read it was the introduction of the .45 GAP that messed us up with Small primers in .45 acp!

I did a limited test between the cases using 5 grains of RedDot under a 200 grain bullet my result showed a 30 f/s velocity loss with small pistol primers . I should probably tried some small pistol magnum primers I may have got that 30 f/s back? Another thing was the standard deviation was very low with small pistol primers HOWEVER the other size primer cases were mixed types civilian and older military so that may be why.

During the same test time I shot conventionally lubed cast bullets powder coated bullets and powder coated bullets with lube the results were all the same speed and accuracy and point of impact at 15 yards. (including Small pistol primers)

There is another thread on this subject somewhere here on castboolits.

[Gunslinger1911]

Sp 45acp - the bane of progressive loaders !
I haven't seen any difference in performance.
Other than a PITA with a progressive press.
My Dillon 550, not a huge deal.
My son in laws 650 - kind of a pain.
Used to be someone on here that would trade sp 45acp for lp one for one. he only loaded 9mm, 357 and 45 acp, advantage to only stock sp.
I need to look around, I have ~a 4 lb coffee can of 45 sp

[fredj338]

The only diff in my tests is a small vel drop with spp v lpp with some powders. Other than the pita factor of sorting, no real diff. I gve my spp brass to a friend that shoots it in a revo.

[jakharath]

I let a small primer 45acp brass slip by while sorting. The 1050 I was loading on tried to put a large primer in the small primer pocket. The primer went off and I nearly had to change my pants. It was loud!

[Bill Allen]

As far as accuracy I see no real difference.But since I also run a 1050 I have to look at each case.Went to the range picked up my brass and got a couple pieces of blazer brass spp in with my lpp brass. Took two times of blowing my primers before I realized what the problem was. So now have to check every piece of brass really slows down the loading

I let a small primer 45acp brass slip by while sorting. The 1050 I was loading on tried to put a large primer in the small primer pocket. The primer went off and I nearly had to change my pants. It was loud!

[Apple Man]

I bought some commercial first fired brass and having a few SPP mixed in the batch is irritating.

[jsanch03]

I’ve recently started comparing both spp and lpp in 45acp through my colt series 70. Using WST powder I had a few unburnt kernels of powder in the barrel with the SPP. I upped the charge ~.2 and the unburnt powder was no longer in the barrel. Not sure if my Winchester spp we’re not hot enough or with WST I just need a little more powder

[1I-Jack]

I realize this thread is about pistol primers (Lg & Sm) but I ran into this on the Starline Brass site when describing their SRP 6.5 Creedmore cases:

Our SR6.5CM brass uses a Small Rifle Primer. Many target shooters prefer the Small Primer for the increased consistency and accuracy. While other small pocket manufacturers use a smaller than standard flash hole, Starline uses our standard .080" flash hole, as we feel that it gives better ignition with some of the slower powders and in cooler conditions* (and you won't be breaking off decapping pins either!) The Small Primer version also maintains primer pocket size much better than the large primer version under higher pressures.

With LRP being almost unobtainium, having a SRP option is awesome.

[rintinglen]

I have never timed swapping SPP to LPP on my Dillon 550, but I am sure I do it in a lot less than 5 min and it's not a pain.

That's only if you can find the darned primer punch in the parts and stuff drawer.

[Rifletom]

As others have mention, I couldn't tell any difference between the two primers that mattered. I load on a RCBS SS, so the spp's don't bother me.

[jsizemore]

Hopefully we've all learned, more options is more better. You never know what you'll run up on.

[Plate plinker]

I let a small primer 45acp brass slip by while sorting. The 1050 I was loading on tried to put a large primer in the small primer pocket. The primer went off and I nearly had to change my pants. It was loud!

Only one went off? When it happened to me I lost a good chunk of the primer magazine tube. And yes it was deafening, my ears rang for a couple days.

[GaryM]

SPP has a potentially stronger case head. A quick email to Starline might be worth the effort.