Load check, 45acp coated 225gn fh

[JRWhit]

Worked up to 6.0 gn of unique behind a missouri bullet 225gn coated flat head, diameter .452. Settled into 5.5gn for the working load. OAL 1.178, fitted to my chamber for .015 headspace.
I need a chrono, i always feel like im flying blind when working one up without something to compare it to.
Using federal lp primer in mixed brass.
I have some data showing loads up to 6.7 gn of unique for a 230 gn lrn. But this seemed quite peppy at 6gn.
What is the most reliable sign of pressure for 45 acp?
Given the pressure range, can you be over pressure without flowwing primers in 45acp?

 

[243winxb]

45 acp High Pressure signs.

I look for what i call a spider web pattern on the body of the brass for high pressure. Some feed ramp/chambers may let the brass bulge if unsupported. I think the thinner web of the 45acp compared to 44mag will let the same primer flow back into the firing pin hole of an 1911 inertia firing pin. I would not hot load a Colt 1911. A S&W 645 can handle it better, IMO. I have loaded Blue Dot to maximum pressure with cast, not Unique. Photo -

The primers shows pressure signs cause by a short chamber in 45 acp, 1911 type firearm. As the action opens the high primer gets primer wipe. A gun smith corrected the chamber problem with a reamer. Not sure i buy this as the cartridge headspaces on the case mouth. Not sure how it could build pressure this way as the bullet is not trapped/ crimped into the chamber like a bottle neck round in a bold action rifle. The 45acp short chamber would hold the action open a tiny amount but still fire if the disconnector was not activated. A bulge might appear near the head if pressure was high. Very Strange.

 

[Walkalong]

Given the pressure range, can you be over pressure without flowwing primers in 45acp?

Yes. It takes a good bit of pressure to flatten large pistol primers. More than 19,900 CUP, IMO.

Primer swipe can be a mechanical problem as well as a pressure problem, but the pressure is there for sure.

 

[243winxb]

SAAMI lists the 45 acp +P at an average pressure of 23,000 PSI. http://www.saami.org/specifications_and_information/specifications/Velocity_Pressure_CfPR.pdf I use WLP in both 45acp & 44mag. I alway wondered about the pressure effect on the primer & reading them. So i measured the brass web thickness of both. The 45 acp being thinner may have something to do with reading primers?? Brass is said to expand, then spring back. Would a thinner web expand more, pushing the primer against the bolt face ?

 

[murf]

excess gunk in the firing pin channel can inhibit the fp return spring and also contribute to firing pin swipe.

murf

 

[au_prospector]

Cannot imagine 6.0 grains of Unique would be anywhere near max. My go to load for .45 ACP with plated 230 grain round nose is 6.0 grains and that seems very mild to me.

 

[JRWhit]

The max load i showed was 6.5gn of unique. But im using a similar bullet and not an exact. The other max load I found was 6.7gn but the bullet design was different enough that I discounted it.
I don't believe I'm showing any pressure signs. No primer wipe at all. Just get that flying blind feeling and as I understand it, pistol loads get into bad territory very quickly rather than giving of little warning along the way.
I went back down to 5.5gn because I saw no difference in grouping and want to save what powder I can. Usually starting low, I see a lot of grit on the sides of the case with a lack of pressure to seal the chamber. These were coming out very clean at the starting load, leading me to think they were getting too peppy to run up to my listed max load.
I could just be dramatically over cautious here. I hate that flying blind feeling.

 

[Safetychain]

If this loading is for self defense, then I understand it would be desirable for a max load. In my experience, plated and lead is used mainly for target and plinking. Why then would I want full roundhouse loads for fun use. I can see in target use wanting to get the most accurate load for your gun but I've found that that is not necessarily the highest loading. Saving on powder and having less recoil problems suggests to me to use a lighter load.

 

[JRWhit]

If this loading is for self defense, then I understand it would be desirable for a max load

It is just for ringing steel. I don't care for max load, just typically do the full work up to see where the best consistancy. In this case I think I'm fine at 5.5gn. I'm just not typically used to finding satisfaction at the starting weght and usually get to about 1/2 work up to find it.

 

[BigBore45]

On Quickload you are showing around 29,000 psi with 6.5 grains. It seems the seating of the bullet is way to deep. OAL should be at 1.275. At 6.0 grains you are still over +p pressure by 500PSI. i would not go over 5.5 grains at that seating depth with 5.5 grains of unique, your SAAMI psi is around 19,280. Just shy of 21,000 which is max.

 

[JRWhit]

On Quickload you are showing around 29,000 psi with 6.5 grains. It seems the seating of the bullet is way to deep. OAL should be at 1.275. At 6.0 grains you are still over +p pressure by 500PSI. i would not go over 5.5 grains at that seating depth with 5.5 grains of unique, your SAAMI psi is around 19,280. Just shy of 21,000 which is max.

Thanks for the data. The bullet has such a broad ogive that oal cannot be any greater without hitting the landings and going negative on headspace. But at 5.5gn it is a decent shooter.

In this case should I Suppose I should have taken notice to the short OAL and started at a lower charge weight?

 

[JRWhit]

This is the bullet and finished cartridge.

 

[BigBore45]

i thinking the reloading data from manufactures is low at the start for this reason and i see no need to start any lower. yes the short OAL is the culprit in the high pressure. i believe that the 6.5 grain load was compressed at that OAL.

 

[243winxb]

45acp - Alliant load data for Unique

Worked up to 6.0 gn of unique behind a missouri bullet 225gn coated flat head, diameter .452. Settled into 5.5gn for the working load. OAL 1.178,

You did the workup, i would go with it.

 

[BigBore45]

see the first load in the pick where the OAL is shorter at 1.19 they list with a 200 gr. as 5.4gr is max

 

[243winxb]

200gr lswc- Not what OP is using.

see the first load in the pick where the OAL is shorter at 1.19 they list with a 200 gr . as 5.4gr is max

The 200 gr Speer lswc is a swaged bullet. Very soft lead alloy. I am guessing the load is not maximum, but a target loading at 790 fps. Only way to know is contact Alliant. Edit add- The printed 2013 data shows loads Bullseye 4.6/807fps & Red Dot 4.5/831fps, higher velocity with same minimum OAL 1.190" for the 200 gr lswc.

 

[BigBore45]

^^^^if they are running that bullet faster with other powders then there must be a reason with Unique it is slower.^^^^

 

[243winxb]

BB45, Your right, seated deeper, more pressure.