bullet setback


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trooks
July 17, 2013, 11:07 AM
I am relatively new to reloading, started in Jan. 13. Up until now have only reloaded for revolvers. I am now trying to reload for my 1911 45 and having problems with bullet setback after chambering. The reload can have an OAL of 1.235 before chambering, after , as low as 1.220 or lower. This is with or without a factory crimp and with as little expansion as possible. Need to figure this out. I am using brass that I bought at a gun show without asking how many times they had been fired.

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bds
July 17, 2013, 11:36 AM
Welcome to THR.

You didn't mention what nose profile bullet you were using but with RN profile 200/230 gr bullets, if I run too short of OAL, the bullet will get seated deeper when the bullet nose bumps the barrel ramp. Using longer OAL can reduce this problem.

Walkalong has an excellent thread to determine the max OAL using the barrel drop test - http://www.thehighroad.org/showthread.php?t=506678

As an example, 230 gr plated RN from RMR/TJ Conevera/X-Treme etc. will produce max OAL of 1.265" and working OAL of 1.263" for my Sig 1911 barrel and won't reduce in OAL when fed from the magazine but if I use shorter 1.250"-1.255" OAL, the bullet will seat deeper in the case neck when fed from the magazine.

Of course, your results may vary depending on the pistol/barrel used.

RainDodger
July 17, 2013, 11:39 AM
With an OAL of 1.235, are the cartridges dropping fully into the chamber with the base flush and not protruding?

I had to drop my OAL to 1.230 with some bullets due to the ogive being in a little different position. The bullet was hitting the lands so I had to shorten my loads a bit. Some chambers are longer or shorter than others. Do the "plunk" test... pull your barrel out of the pistol and drop a loaded cartridge into the chamber. It should fall in, and be fully flush at the base.

rsrocket1
July 17, 2013, 11:54 AM
A few questions:

Are you using lead, plated or jacketed bullets?
How much flare is "as little as possible"? Is it so little that you run the risk of the bullet falling off the case as you raise the ram or do you mean you expand the full length of the bullet into the case as narrow as possible?
With a bullet seated into a flared but uncharged and deprimed case, can you push the bullet any further into the case with your thumb? Can you push the bullet in by setting it upside down with the force of you hand? Can you do it with your weight behind it?
Do you use a Lee Factory Crimp Die in the final stage?

trooks
July 17, 2013, 02:36 PM
Until someone mentioned nose profile I did not realize I was reloading a copper coated SWC , 185 gr. Got a deal on them at a gun show. To answer some of your questions. I have tryed lengthening the OAL to take up for the set back When I do this they will not chamber at all. Haven't tryed the " plunk test " yet , but I will. I do have the Lee factory crimp. Have used a light and heavy crimp. In expanding as little as possible my bullet does stand the chance of falling off the case. Could old brass contribute to this problem ? Like I said I am new at this but want to learn. Can you measure how much you are expanding ? Do SWC load differently.

rcmodel
July 17, 2013, 02:51 PM
Take your expander out of the die and measure it.

It should measure no more then .449" - .450".

If it is bigger then that, chuck it in a drill and work it down with emery cloth or paper.

It's also possible for excess taper crimp to make the bullet looser rather then tighter in the case.

The brass case has more spring-back then the softer copper & lead core bullet.
So if you over-crimp and squish it, the case springs back away from the bullet.

Measure your crimp at the case mouth.
It should measure no less then .469".
But .470" - .471" would be better.

rc

Drail
July 17, 2013, 08:28 PM
And once again RC hits it on the head.

gibble888
July 17, 2013, 09:07 PM
Would a roll crimp be better than a factory crimp?

rcmodel
July 17, 2013, 09:12 PM
NO!

You can't roll-crimp straight wall auto-pistol calibers, as they all headspace off the sharp edge of the case mouth.

That's why they are taper crimped and not roll-crimped like rimmed revolver calibers.

rc

gibble888
July 17, 2013, 09:26 PM
Copy that...just askin cuz i only load for rifle right now...p.s. holy crap u have lots of posts...lol

Centurian22
July 18, 2013, 03:59 AM
Yes he does, RC is nothing short of a ledgend around these parts, especially in the reloading department. Trooks welcome to THR and good luck, I hope the 'plunk test' helps narrow down the problem for you.

gamestalker
July 18, 2013, 05:13 AM
Welcome to THR!
There are various aspects to preventing come of the causes of set back, and some revolve around the type of bullets concerned.

A particular manner of seating jacketed bullets that I've been using for a number of years has quite honestly eliminated most if not all of the issue for me. When I'm loading 9mm or .40 I don't use any crimp at all, cause I don't bell the mouths at all. I simply do a quick even chamfer of the mouth, set the bullet on top, which will set up straight on the mouth, and then just seat. It's faster, and it provides the maximum possible degree of neck tension, and consistency of such, round after round. I've also noticed that my velocities are considerably more consistent too.

I've never tried it with anything other than jacketed bullets though, and I highly doubt this would work favorably with anything but jacketed, maybe TP plated bullets, but don't know for sure. But with jacketed bullets, it's slicker than snot.

GS

trooks
July 19, 2013, 12:18 PM
Thanks for all the advice. Using only once shot brass, a little more expansion and no factory crimp at all resulted in no setback. Dummy loaded a magazine fulll and all chambered and ejected smoothly. Thanks.

PapaG
July 20, 2013, 03:08 PM
I know that the purpose of a taper crimp is to remove the flare. (Been at this for fifty plus years and no kabooms, I err on the side of caution). That said, you can screw that taper crimp die down too far. I did so years and years ago on some 45 acps and premium 185jhps. Figured that a little "crimp" was good, more would be better. After crimping "heavily" I luckily noticed that the bullets were loose in the cases whereas before they passed my "push test". I dropped a few of the .4515 dia bullets out and miked them....they were now about .448 diameter and useless.
A word to the wise.

herrwalther
July 20, 2013, 04:01 PM
Also the best way to reduce bullet setback is to chamber a round as little as possible. Keep an extra set of calipers in your cleaning kit to measure bullet setback of your carry weapons. If a bullet is setback a noticeable distance, either put it aside as range ammo or dispose of it. Either way, take it out of your carry rotation. Welcome to THR.

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