45 ACP - SPP Load Development

[afate45]

I have countless pieces of .45 ACP with small pistol primers, primarily Blazer brass that I find in abudance on the ground at a local range. I decided that I wanted to do a load development just so I have the data in case I ever need to use this brass and because I have 2x as many small pistol primers as large. It was an interesting day at the range. I am no expert reloader, so let me know if I'm missing something here.

Here are the highlights, then I'll go into the specific load data. - The ES/SD was huge (not going to list all the data, but you'll see the how wildly the small pistol primers performed in the velocity chart below).
- I contribute the ES/SD to the fact that SPP are too weak for the 45 cartridge, at least with the components and recipies I was using
- I noticed velocity would dip up and down as I went up in charge weights, so I tried tapping the cartridge on the table to put the powder at the back before firing. This yielded over a 100fps difference! I don't know about you, but that scares the hell out of me. If I push the load to near max, but it has the potential to go 100fps over, that's just asking for over-pressure situations. Maybe not kaboom territory, but probably blown primers and/or wear on the gun. I can do the same thing with a LP load, and maybe see a 20 fps difference.
- Small Pistol Primers in the upper charge weights appeared to have an extremely deep dimple in them. I'm shocked they weren't peirced/blown. I don't have pics, sorry. All else considered though, there were no other signs of pressure...including chrono results at those charge weights. Anyone else experience this?
- I captured velocity data for Large Pistol vs Small Pistol

Equipment Used:
Dan Wesson Valor - 5in
S&W M&P .45 - 4.25in (note, all velocities below were recorded in the 1911...everything was just slightly slower in the M&P due to barrel length)
A-1 Chrony
Loaded with Hornady LNL, individually weighed charges on RCBS Range Master scale


Load:
.45 ACP
Blazer small pistol primer brass, Winchester Large Pistol Primer brass
Hodgdon HP-38
Winchester Small Pistol Primers
Federal Large Pistol Primers
Hornady 185gr XTP (LNL promotion bullets...woohoo)
1.205-1.208 OAL (This OAL is about .010 from the lands in the M&P, .015 from the lands in the 1911.)
Taper crimped to .469
Case mouth bell to .471...barely belled due to longer OAL for this bullet (load book recommends 1.175oal) and chamber set-back tests showed the bullet was knocked back into the case .005-.010 with a larger bell.

Now the interesting part. Look at the velocity as I go up in charge weights for the small pistol primer.
***note, LP = large pistol primer, SP = small pistol primer. Use these loads at your own risk, be sure to work up before starting at any one of these charge weights.

5.1gr...LP=605, SP=513 (SP did not cycle slide)
5.4gr...LP=651, SP=730 (tapped SP load on table before firing)
5.6gr...LP=730, SP=633 (SP barely cycled slide...brass almost landed on top of slide)
5.8gr...LP=790, SP=691
6.0gr...LP=851, SP=700
6.2gr...LP=866, SP=881 (Heavy cratering of SP started here) (181fps difference in 0.2gr charge weight increase???)
6.4gr...LP=870, SP=886
6.6gr...LP=896, SP=861


I believe the Lyman reloading book lists the max charge weight around 6.2 or so, but since I am using a longer OAL, I have plenty of room to go. I'd like to shoot for around 950fps or so, but I don't think that is possible or even safe with the SPP. I'm guessing 6.8gr-6.9gr will be the sweet spot for a max load, with the LPP. 6.6gr is definitely a nice shooting load, and is deadly accurate...with the LPP. That's the load I'll probably use for the remaining 460 Hornady XTPs.

I was hoping to leave the range with a load I could use for SPP, but now I'm scared to load anything but a bunny fart load around 5.8-6.0gr with the SPP. That way when it's 100 degrees outside, the powder is jammed to the back of the case 'cause I've been running around, I don't have to worry about blowing primers or beating up my slide and frame all day long.

I'm 100% open to criticism, feedback, shared experiences, etc. Thanks for reading.

 

[Yasherka]

I thought Blazer was aluminum cased and berdan primed? Did they make a change at some point? Not being snide, I haven't bought any blazer in a long time.

 

[leadbullet]

try a 230 gr FMJ with 4.8 gr of clays, works great for me in SPP brass.

 

[LARMIKE]

First is your pistol able to shoot a tight group? You can alter the crimp from .469 to .471 It might be a good thing to check the actual bore diameter, dont guess either. If the barrel is tight it may take a faster powder to get your accuracy you require. Larger bore = slower powder, Also VV 310 and Bullseye are very good powders to use for tight bore.45 Hope this helps.

 

[DirtyRod]

Sorry if I missed it but are the velocities averages of 5, 10, X rounds?

 

[afate45]

Thanks for the replies everyone.

Yasherka - The Blazer brass is indeed brass, not aluminum. No harm in asking! They have a line of ammo that is reloadable brass. Blazer - Blazer Brass

LARMIKE - Yes, the 1911 is extremely accurate. I haven't done any testing with the M&P, it has more or less been a safe queen with less than 500 rounds down the tube. The 1911 on the other hand has thousands of rounds through it (I forget exactly how many...probably around 4k or so). I guess slugging the bore is something I could do, never thought of that. The 1911 eats Zero 230 RN and JHPs like they are going out of style, same with Berry's 230 RN. In accuracy tests my 1911 has kept up with two of my buddy's Les Baers.

I think you all hit on an interesting point though...HP-38, my beloved pistol powder, is probably not the right choice for a SPP load. Another factor may be bullet weight. Trying to push a 185gr .451 bullet to 950fps with a small pistol primer may not be possible without switching powders.


I'm still curious though, anyone else have input on what is causing the insane variations in velocity with the small pistol primer? As you can see, the large primer loads were right about on-par with where they should be velocity wise.

 

[LARMIKE]

You also might consider going to a lower velocity, say areound 800 fps.If you are shooting pistol matches I would go with lower velocity for sure.

 

[afate45]

After additional testing this last Saturday, 900fps with a large pistol primer seems to be the sweet spot. I agree with you Larmike, 800fps is probably where I should stick when making rounds with small pistol primers.