reloading everyone's favourite .45ACP

phatman

phatman

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I have got a question about Cartridge Overall Length.

I've been working on a load for 45ACP using Universal Powder, 230gr plated RN bullets, Winchester brass and primers.

Hodgdon's 2009 Annual Manual lists the COL for this combination as 1.200", yet the maximum for this cartridge is 1.275".

I had always thought that it is best to leave the cartridge as long as possible because:

a) less jump because the bullet is closer to the rifling
b) feeding reliability.

Is there any advantage in reducing the COL to less than maximum?
 
The .45 ACP is a low pressure cartridge & is more forgiving with respect to pressure
changes due to seating depth.
IMO I would not be concerned with bullet jump to the rifling in a 45.
Because the cartridge enters the chamber at an angle with the nose up and
actually the nose touches the top of the chamber during feeding, reliable
feeding in YOUR gun is the prime concern.

I would also ensure that you use good quality mags & that the feed ramp is smooth.
 
Different bullet shapes require different OALs to function correctly. Whatever bullet Hodgdon used to work up their data may not fit the chambers of most pistols if seated for an OAL of 1.275". Ultimately, you must fit the loaded round to your chamber rather than chasing a number from a manual.
 
My main concern here I guess was seating depth vis-à-vis pressure changes. I wondered if Hogdgon had chosen 1.200" for their tests because that depth had provided the best chamber volume for combustion with that combination.

Thankfully my pistol is pretty forgiving with respect of COL. I ran 30 rounds through it this morning (1st test run 5x each load) at 1.275" ran flawlessly.

made up a mag of dummy rounds at 1.200" last night - seemed to cycle well - but it's hard to say if they would work with powder in them - maybe I'll assemble a run of them tonight and see what happens...
 
take the barrel out of your gun, and drop in your dummy rounds, they should make a metallic sound when drop into the chamber. it should also drop out by simply turning the barrel upside down. if your OAL does that AND fits your mag AND cycles like you said, your good to go.,
 
hatman1793 said:
You never mentioned what the application was for. Most 45acp reloaders use the 200 grain bullet as standard. Why 230? The classic target load out to 50 yards is a cast 200 grain lead SWC behind either 4.0 grains of Bullseye or 4.1 grains of RedDot.
Click to expand...

or 200 lswc C-700X @ 3.9gr, 230-lrn, C-700X 4.1..excellant loads for paper/melon punchin' eeha the "professional series" :)
 
IMHO:

1) Jump = don't worry about it.

2) Feeding = long is good

3) COL = 45 ACP is very low pressure, as others have said, but because of its relatively large X-section a significant change in COL causes a significant change in volume & pressure, even though this remains at the low end of the scale. Changing COL can change POI for a given (preferred) sight picture, all else (powder charge) being constant.

4) During the "clunk" test described above, you may want to apply some thumb pressure to the head of the cartridge before inverting the barrel to see if the cartridge will then drop out on its own.
 
HKMark23 said:
IMHO:

3) COL = 45 ACP is very low pressure, as others have said, but because of its relatively large X-section a significant change in COL causes a significant change in volume & pressure, even though this remains at the low end of the scale. Changing COL can change POI for a given (preferred) sight picture, all else (powder charge) being constant.
Click to expand...

Ok this is what I'm thinking - in every workup that I have done - I've started with the bullet just off the rifling and adjusted powder grs from there -

In this case - and those of you that have .45s know - that there is no way you can fit the cartridge in the mag and have it 10-20 thou off the rifling.

Lymans is a big company that have done testing for decades, so why do they have different COL for different combinations?

why would they not just publish the recommended grs for each powder at the maximum COL for every calibre?

There must be a trade off between the efficiencies of the pressure curve of the smaller internal volume of the 1.200" COL and the stability lost due to the increased jump of the test cartridge.

Inquiring minds want to know - unless of course it is a completely arbitrary call on the part of the technician on that day
 
hatman1793 said:
You never mentioned what the application was for. Most 45acp reloaders use the 200 grain bullet as standard. Why 230? The classic target load out to 50 yards is a cast 200 grain lead SWC behind either 4.0 grains of Bullseye or 4.1 grains of RedDot.
Click to expand...
The standard ball ammo for 45 has always been 230, that is all I have ever reloaded.
 
Well it has been a week since my last post and here is what I have done in the interim -

I loaded up a 'test' tray of ammo, 5.1gr - 5.6gr Universal Powder, 230gr plated RN bullets, Winchester brass and primers, 5 cartridges each at 1.200" COL

Had a very good group at 5.2grs, I have no idea of the pressure or the velocity - I am only loading for grouping.

Disclaimer - I am only using a rifle rest for this - if I wanted to get really anal I could get a Ransom rest (which I have thought of...)

However in the end I made a judgement call and went back to 1.275" COL simply for the reasons I outlined in my OP.

Again I had a very good group at 5.5grs - which is getting up there pressure wise - and I'm getting good chamber sealing from brass expansion - evidenced by very little powder residue on the outside of the expended cartridge case.

I'm going to play with this for awhile - I am considering testing variable rate recoil springs abit to see if I can find the perfect cycling action - low perceived recoil along with reliable feeding - any ideas?
 
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The Max COL is what will fit your particular brand of magazine and still be clear of the rifling. Who cares what mag and gun the lab used? I start long and seat deeper until the gun cycles well. 1.225" comes to mind.
 
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