45 acp brass - primer size vs bullet grain

[coebam]

Guys- sorry if this has been covered - I looked and did not find the answer I was looking for. Obviously the .45 ACP brass can have both L & S primer pockets. Is there a line at which the grain weight of the bullet necessitates the use of the large primer pocket?

For example my home defense rounds are factory 230 grain hollow point - large primer. I believe I have factory 185 grain target round cartridges that use the small pocket.

How do I know when I need the large primer pocket?

Thanks for the help in advance!

 

[rcmodel]

Primer size has nothing to do with the bullet weight or powder type or charge.

The .45 ACP has traditionally used Lg primers ever since it was invented in the early 1900's.
Until recently when lead-free primers came along.

Non-Toxic or lead-free ammo uses small primers to prevent gun damage from the more powerful Dynol priming compound.

rc

 

[918v]

Currently, leaded ammo uses the small primer pocket as well. I like the small one better. It is more accurate.

 

[john16443]

I reload both and use the same powder charge regardless of primer size. I like having access to the small primer casings as large pistol primer isn't always as available as SP in these parts.

 

[GLShooter]

Maybe the question to ask is if we really need a different size primer for different weights why did we use an LP for going on a century?

The SP cases aren't giving us any better performance and they are linked to the non=toxic ammo most of the time. I think Blazer just does it for the heck of it!!

Greg

 

[918v]

Because the 45 ACP was based on the 30-06 casehead. That's why the large primer.

 

[GLShooter]

Because the 45 ACP was based on the 30-06 casehead. That's why the large primer.

Good point. Food for thought..

When the 40 S&W came out it had a LP prime. It now uses small ones. Why? I think I know that one.

The 10 MM is produced with both sizes. Is there a benefit one over the other?

Are there performance improvements with the SP on the 45 ACP?

Greg

 

[coebam]

Oh...Maybe I'm seeing the light of day here. Do we use the large primer pocket to ignite a higher amount/quanity of powder?

 

[918v]

In my testing (using a match tuned revolver and 1911), the small primer produces better accuracy. For example, FC-100 is at least 33% more accurate than FC-150 in my guns.

 

[918v]

Do we use the large primer pocket to ignite a higher amount/quanity of powder?

Not in the case of the 45 ACP.

 

[GLShooter]

The powder charges don't change in the pistol cases we are looking at. Some rounds may be more accurate at times with some powder types but an across the board statement might lack in applicability. Perhaps the factories have a powder we aren't using or some such but I firmly believe it is more marketing ploy in handgun rounds.

The 40's were haveing issues with rounds going off when they were being ejected and hitting the fixed ejectors on 1911's ( I have witnessed that!! Not Good)

We do see a change in accuracy in some center fire rifle stuff that seems to indicate the SR primers work better on the small capacity accuracy oriented cases.

Greg