Resizing 45ACP brass with 45 Long Colt die

Hi all.  I'm new to reloading, and I'm in the process of trying to get my reloading equipment squared away ... specifically dies (I'll be using a Dillon RL 550B).  I read a recommendation somewhere to use a 45 Long Colt resizing die on 45 ACP brass, for the reason that 45 ACP resizing dies tend to leave the case wall narrower than the base of the case, and that the .472 inches vs the .469 inches of a 45 ACP resizing die eliminates this issue.   I was just wondering if this is something most BE shooters practice?  Thanks.

SIGcurious wrote:Hi all.  I'm new to reloading, and I'm in the process of trying to get my reloading equipment squared away ... specifically dies (I'll be using a Dillon RL 550B).  I read a recommendation somewhere to use a 45 Long Colt resizing die on 45 ACP brass, for the reason that 45 ACP resizing dies tend to leave the case wall narrower than the base of the case, and that the .472 inches vs the .469 inches of a 45 ACP resizing die eliminates this issue.   I was just wondering if this is something most BE shooters practice?  Thanks.

...No,  this is not something most BE shooters practice.

Redding has a die that sizes the case lower down than Hornady or Lee Dies.

I tried it, saw no benefits from using it. Went with reddings two ring size die which does it much better.

rich.tullo wrote:Redding has a die that sizes the case lower down than Hornady or Lee Dies.

Are you referring to the Redding 2 ring size die, or the regular?  Thanks.

I have Dillon dies in my press but I size and decap before polishing with Lee dies. They seem to work fine IF the bras was not shot through a Glock first. Unknown once fired brass gets run through a Lee bulge buster.

All else fails run them through a Lee budge buster... Sizes the rim too


I have done this through all my old cases to resolve some feed issues

Reading you original post again it sounds like you are concerned about the final inside diameter of the case, as it is ready to load the bullet. trying to get a bigger I.D. by not sizing the case as small and counting on the case wall thickness to stay consistent. Just my opinion but I think you are far better off to size the cases with the proper dies (any of the dies mentioned above will do a good job) and tailor your expanding tool to give you the case tension you want. There have been lengthy posts on what is best and how we all like to go about doing that process so search that. There is always room to experiment if nothing seems to suit you. It's good to understand the history of the various rounds involved too. Barrel, chamber, and bullet dimensions for .45 caliber have varied over the past 150 some odd years. You need to understand that the 1911 becoming the standard military pistol changed a lot of other guns in small ways because it didn't make sense to keep making many different "standard" sizes

If new to reloading, best to assume the companies know what they are doing when making dies and just use the standard dies. The standard dies work for about 99.9% of users.
Get a few years under your belt before experimenting or believing what you read on forums.

> for the reason that 45 ACP resizing dies tend to leave the case wall narrower than the base of the case.


Tradionallly, the .45 Colt uses a 0,.454" bullet and the .45 Auto uses a .452" bullet. IF not sized down enough, you won't get enough bullet tension and the bullet can be pushed into the case during feeding and chambering.
Not sure what you mean by the case walls being narrower--only assume you mean the case OD/ID is smaller.
You don't need anything beyond the norm.
Re: sizing further down the case
The Lee and Hornady size a bit further down than the Dillon, but only the old RCBS carbide dies that has almost NO chamfer could size down much further.
The .45 Auto is a low pressure case and shouldn't need a bulge to be ironed out.

jglenn21 wrote:All else fails run them through a Lee budge buster... Sizes the rim too


I have done this through all my old cases to resolve some feed issues

I hesitate to use the bulge buster as a rim resizer.  Rims smashed too much broke the carbide in a LFC for me, while none of the cases seemed to need de-bulging.

yes i have that Redding two ring die does a great job.

if you slightly oil the cases it really helps the budge buster.. I only do this on rims over .478 in diameter.


I'll assume Lee replaced your die.

My brass is matched headstamp Winchester police range pick up. I ran it all through a Lee bulge buster, on the first prep, in case any of it was Glocked. Aside from that, I'm planning on sticking with Dillon dies and not bulge-busting again. This is a new batch of brass for me, so no real experience to share, but I was faced with similar questions, and this is what I'm doing.