Feeding problems, 45 ACP


September 28, 2011, 09:49 AM
I keep having problems with some of the .45 loads (230gr) feeding in my M&P 45. It seems that the slide does not go all the way forward on the ones that won't feed. I figure they maybe too long or not crimped enough. The OAL on most of them is around 1.252 to 1.255. Lymans lists the max OAL should be 1.275 so I am well under that (or maybe I am cutting it too close to the max)

Any thoughts, suggestions?

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September 28, 2011, 10:01 AM
You didn't indicate what style bullet, at 230 grain I'm guessing round nose. You're indication of length and/or crimp as the likely culprits is probably correct.

That OAL you provide would NORMALLY work in most 45's but the only way to know for sure is to check it in YOUR barrel. Drop one of your rounds in the barrel, if you don't hear a 'plunk' sound and the round isn't even or very slightly below the barrel hood, you have a bullet that's too long or the crimp isn't enough to allow the round to headspace properly. When you turn the barrel upside down, the bullet should easily drop out.

Take a magic marker or something and color the exposed part of the bullet. Drop it in the barrel again and rotate it around a few times. Remove it and examine. If you see any sort of line or marks that have removed the color, your OAL is too long for your barrel.

What is your crimp? It should be .469 to .472, and you should not overcrimp or roll crimp these rounds. Get just enough crimp to straighten the case (remove the flare or bell) and you should be OK.

September 28, 2011, 10:15 AM
Yes, it is a 230gr round nose plated bullet. I pretty much have the crimp turned back on the bullet seating die and am using the FCD.

BTW, how can I quantify the crimp, e.g. .469?

September 28, 2011, 10:50 AM
I use a digital caliber guage. There are many here that use the .469. I find on plated bullets that they are very soft and tend to deform at the case mouth, therefore, I don't go below .470. Take a look at the bullet/case mouth area and make sure you are not buldging the bullet. Just take out the flare.

September 28, 2011, 11:34 AM
Some tight match grade barrels will require taper crimp to .469"

Most factory jacketed loads using .451" diameter bullets will be taper cramped to about .470"

I taper crimp jacketed bullets to .470" but use .471"-.472" for lead .452" diameter bullet which falls in freely in my Sig1911 and M&P 45 chambers.

September 28, 2011, 01:56 PM
Just to be clear, when you do the drop test, remove the barrel from your M&P, then drop the loaded round in. The ogive of your bullet may be different from the one in the manual so you need to set the OAL based on your bullet in your barrel.

September 28, 2011, 02:06 PM
I have the same problem with my S/W 645, I had put to much Bell in the case, I found out you just need enough to hold the bullet.

September 29, 2011, 03:46 PM
Had same problem with my 1911. what happend in my case was when i seated the bullet it was not straight with the case and being crooked put a slight buldge on one side. have bought a hornaday seating die with alining sleve but havent tried it yet.

September 29, 2011, 05:09 PM
The simple solution is to get a Case Gage and check your rounds. There are several different ones to choose from, and are reasonably priced. Such as this one at Midway USA: http://www.midwayusa.com/viewProduct/default.aspx?productNumber=171349


September 29, 2011, 05:14 PM
Better yet, get a digital caliper and set your taper crimp die to produce a cartridge squeezed down to a 0.470(-) diameter case mouth.

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