Help with .45 Auto COAL/Powder charge

[Its 45 Colt]

I recently purchased some 185gr JHP bullets and decided to load them with 2 different powders to see how they differed. The first powder was W231, the load data called for a COAL of 1.200", I loaded them that way and the case mouth was just below where the ogive starts,,,all is good.

Then I loaded some with Universal and the load data called for a COAL of 1.135", I loaded them to that COAL but it caused the point where the ogive starts to be a good bit below the mouth of the case. I did cycle them through my pistol (not firing) and the whole magazine cycled through with out issue. I do not think these rounds will miss feed or give any problems, it just looks strange to me,,,is it???

I got to thinking if I could make the COAL 1.200"? Would I need to adjust the powder charge? If so what is the formula to make this calculation?

I would think that making the COAL longer than what is specified in the load data would reduce internal pressure,,,but by how much? would I just work up a ladder test to get to the same velocity as the original load?

While I am at it,,,I have some 255gr LSWC bullets that I want to load for my .45 Colt. I want to use Universal powder but I am unable to find load data for that powder with a lead bullet. I have found data for lighter and heavier bullets,,,so,,,how would I go about working up a safe load for the 255gr LSWC???

Please do not just throw load data my way,,,I really want to learn how to do this work.

Thanks
Eric

 

[Jim Watson]

I consider OAL to be determined by the bullet, not the powder. The loaded round must fit the magazine and the chamber and travel from magazine to chamber.
I have ammo the same OAL with three different powders.
Did your 231 and Universal loads call for THE SAME bullet at differing OAL?
A 185 at 1.200" sounds like a Hornady XTP, 1.135" is what Hodgdon shows for both powders and a Hornady JSWC.

If I were making a large reduction in OAL I would reduce the load and adjust back to the desired velocity. If making a large increase in OAL, I would adjust to the desired velocity. I do not seat bullets with ogive below the case mouth.


Hodgdon has .45 Colt Universal loads for 250 and 260 grain bullets. They are very similar, I would not get exercised in a recipe hunt for specific 255 bullets.

 

[Walkalong]

Good advice from Jim on both questions.

I got to thinking if I could make the COAL 1.200"? Would I need to adjust the powder charge? If so what is the formula to make this calculation?

The max will be slightly less, but there is no "formula" for it.

Follow Jim's advise.

 

[joneb]

I load Nosler's 185gr JHP at 1.195" any long than 1.2" and the rounds will not pass the plunk test in my Colt 70's ser. chamber.

 

[Walkalong]

I run the Zero 185 Gr JHP to fall between 1.220 to 1.225 OAL. Passes my Colt Series 80 Enhanced.

Load your 185s at the 1.200 that worked with W-231 so the ogive will not be below the case mouth, and stop at your desired feel/velocity/accuracy, or stop 2 or 3 tenths short of the max data.

 

[Its 45 Colt]

Thanks for the info. That is what i was looking for.

Since i started reloading,,,for the most part I am self taught,,,I have seated to the minimum. That will now change.

It is time for more experimentation,,,and more learning.

Thanks again

 

[LiveLife]

185gr JHP ... W231, the load data called for a COAL of 1.200"

... Universal and the load data called for a COAL of 1.135"

COL/OAL listed in published load data used for pressure testing is not the "suggested" length rather just the length they used for particular test barrel in a universal barrel fixture that is often single shot action that do not need to feed from the magazine.

For this reason, when we conduct load development for semi-auto pistols that feed from the magazine, we must determine the maximum OAL then working OAL that will work with our pistols/barrels/magazines.

Walkalong has an excellent thread for determining max OAL using the barrel - https://www.thehighroad.org/index.p...rel-find-a-max-o-a-l-with-your-bullet.506678/

And as Jim Watson posted, OAL is also not determined by the powder, rather bullet's nose profile (also known as ogive) and where the bearing surface exist on bullet base (part of bullet base that will engage and ride the rifling).

I have seated to the minimum. That will now change.

It is time for more experimentation,,,and more learning.

Often, JHP/HP nose profile is CN/RN profile with tip cut off. If you look at the comparison picture below of factory PMC/CCI ammunition compared to my reloads with Berry's RN and HSM HP, you will notice different OAL but similar bearing surface of bullet base at case mouth (Imagine the rounded tip on top of HSM HP).

So use the barrel "plunk" test to determine the max OAL (Walkalong's linked thread above) and feed/chamber dummy rounds (no powder/no primer) from the magazine and incrementally decrease the OAL until rounds reliably feed and chamber - This is your "working" OAL.

I would think that making the COAL longer than what is specified in the load data would reduce internal pressure,,,but by how much? would I just work up a ladder test to get to the same velocity as the original load?

For chamber pressure, it's not the OAL rather bullet seating depth where bottom of the bullet is seated to that affects pressure build.

We calculate bullet seating depth by subtracting bullet length from the OAL.

I did max case fill calculation on this post for you to reference - https://www.thehighroad.org/index.php?threads/red-dot-9mm-and-case-fill.848934/#post-11078957

Often, JHP/HP will end up with deeper seated bullet base than FMJ/RN and will require lower powder charges but for lower pressure 45ACP, starting with published start charge should be good enough for your powder work up. For higher pressure 9mm/40S&W, I will often reduce start/max charges by .2-.3 gr when I use significantly shorter OAL than published OAL.

 

[Jonesy814]

Often the OAL listed is a minimum. If so there is no harm in going longer based on your specific bullet
Unless you have the exact same brand of bullet they used the OAL you use will in many cases be different.