45acp bullet setback 1911

[Msfinlayson]

I am getting i little bullet set back when hand cycling here are my specs. I have been reloading for a little while and just bought my first chrono and trying to get my es and sd more in check so i have been looking over every thing. Hand cycling my setback is .0015 but when dropping the slide release it is .004 The gun is an STI Spartan. Is this acceptable or should there never be any bullet setback. Thanks

Dillon 650

Lee sizing die

Lee seating die

Dillon Crimp die (.470)

Oal is set at 1.250

Bullets Xterme Plated 200 gn rn

Edited December 16, 2012 by Msfinlayson

[Sarge]

Any setback is unacceptable. Period. Try loading different headstamps and see if it improves, gets worse, or stays the same. Try to narrow it down to one or two brands of brass. I found in 9mm that FC and CCI had thinner case walls and I was getting setback with only those two brands.

I got an EGW Undersized die and all setback issues went away. You may want to consider the same.

[A45100]

I had a lot of set back issues with the bullets you're running. You might want to try jacketed as apposed to plated.

[RiggerJJ]

The Udie is the only thing I found that eliminated setback...

jj

[Msfinlayson]

I am changing bullets loaded the last 500 up for steel loads. I was thinking about trying some of the Bayou Bullets. I was also looking in to the Udie. Is there any down falls of using the udie or any reason not to. Thanks

[Sarge]

If you don't lube cases the Udie can be a bear to run brass through. Even with lube the die requires a little more effort than a standard die. But those certainly don't fall into the realm of "Down Falls" in my opinion.

[leas327]

Try running your crimp at .469. Everybody measures different when we are talking about .001. With a plated bullet you can only crimp so far. Eventually you with either swage the bullet down too small or cut the plating. Run the crimp die down a little farther, then take the round out and use a hammer puller to take the round apart. Measure the bullet when the case mouth is. It should still be the same diameter as a new bullet. Look for cuts in the plating. If those are good, load another and check for setback.

[Msfinlayson]

I already lube all my cases will never go back. I have tried a tighter crimp setting the set back was still present if not worse. I am going to be changing bullets and ordering a udie. I will let you know how it works out

Edited December 17, 2012 by Msfinlayson

[superdude]

0.004 inches setback is nothing to be concerned with, IMO. It falls within the range of "normal." Why do I say this? I have data.

I measured setback from 240 rounds of factory 45 ACP ammo run through a 1911 by releasing the slide lock. Of those, 180 had setback of .002 or greater. That's 75%. 127 had setback greater than 0.005 inches. The average setback was 0.011 inches. Really. The greatest single example was 0.035 inches!

Ammo was a variety and included FMJ, plated, JHP. All varieties showed setback. Some more than others.

By those standards, your 0.004 inches is well within the range of normal. 0.004 inches will not adversely affect pressure to any significant degree, at most a few hundred psi (and see the example below), and if your margin of error is that small then you're going to run into trouble anyway.

Keep in mind that we never (realistically, never) check for setback when we're at the range, unless there is a feeding malfunction and we happen to look at the jammed round. Otherwise, if it chambers, we shoot it. Right? Think about all the ammo you've sent down range. Did you check for setback on any of those rounds? Hell, I don't. If it chambers, I pull the trigger. If the average amount of setback did blow up guns, or blow cases, we'd be doing it all the time, like every magazine full.

I'm not saying that you should ignore setback and not be concerned with it. But I am saying that it is far, far more common, and more severe than we probably recognize. You've done the right thing to check for it. But realistically, 0.004 inches is nothing.

I can't give you, or anyone, a number that will stand out as to when we should be concerned with setback. We know that setback will increase pressure. But we do have a margin of error for our loads, with the margin being much smaller for stuff that is on the edge or exceeding SAAMI specs. The concern is not so much blowing the gun as it is blowing a case. Guns (barrels) are supposed to be able to take proof loads which exceed SAAMI standard pressure limits by 130%. In the case of 45 ACP that puts the proof load at 27,300 psi (minimum). (See the SAAMI publication for details on how this is calculated. You can find it here: http://www.saami.org/specifications_and_information/index.cfm).

Ramshot published a chart in one of their older load manuals that showed pressure change as a function of OAL for a 9mm and .40 load. (Unfortunately it is not in their most current load guide.) The 9mm data was for a 115 grain bullet loaded with 4.5 grains of Zip gunpowder. Ramshot lists ZIP on the same line as Winchester 231 on their burn rate chart. The lowest and highest marked pressures went from about 27,500 psi to about 32,800 psi. That covers a range of 5,300 psi. The overall length values were from about 1.083 inches to about 1.155 inches, for a range of 0.072 inches. Feel free to check my math. Based on those estimates I calculate a change of approximately 736 fps for every 0.010 inch change in OAL. So, there is an estimate of pressure change based on published information. It's not 45 ACP data but it will have to do for the present. It does suggest that pressure change is not extreme with small changes in OAL. Oh, and the change appeared to be linear.

How much pressure the brass will take at the unsupported region is a different issue, in part because the unsupported region can vary depending on the manufacturer/gunsmith, and the brass itself is another variable. But brass failure is the bigger concern.

I used to think that plated bullets were the worst offenders when it came to setback. Actually, I still do, but I've also seen loads with plated bullets produce some of the least setback, so nothing is certain.

The bottom line: pay attention to setback but don't freak out about it. It is, unfortunately, "common." And in my opinion, 0.004 is nothing to worry about. But folks are entitled to their own view on the matter. Again, I can't/won't say how much setback is too much. You have to set your own limits. But based on my data I personally wouldn't worry a bit about .004 inches.

[fredhull]

New to this, what's "SET BACK" I load 45acp and no issues Glock Sig or 1911.

[Dirty Rod]

New to this, what's "SET BACK" I load 45acp and no issues Glock Sig or 1911.

It's when the bullet gets pushed back into the case usually from clambering the same round over and over.

http://www.bing.com/images/search?q=bullet+setback&view=detail&id=888ED37AED16468D90C13302D443427BF7821F2A&first=1

Edited December 22, 2012 by Dirty Rod

[Msfinlayson]

New to this, what's "SET BACK" I load 45acp and no issues Glock Sig or 1911.

Bullet set back can happen after only one chambering that is what is happening with my 1911. It changes the pressure and can cause inconsistency in your load. My OCD want the least amount possible so if the EGW udie will make it go away then thats what I will try. It should be here tomorrow I will try it out and let you now what i think. I use mixed brass from a indoor range so all different head stamps which can have different case thickness. My 9mm for my Xdm have zero set back so more than one thing can cause bullet set back but it seams to all come back to neck tension on the bullet.

Edited December 22, 2012 by Msfinlayson

[Msfinlayson]

Just received EGW u die installed it and no more bullet set back. Will have to test and see how if any change it has on my chrono results. Thanks Everyone for the help.

[GregJ]

The Udie is the only thing I found that eliminated setback...

jj

This ! I shot Bayou 200g SWC bullets for over a year, and had to seperate my match brass to all higher grade headstamps, but still would have the occassional setback causing a 3-pt jam, or some other malfunction. I got an EGW U die, and switched to 230gr Zero bullets, and can load any and all brass with no setback issues.