45 reloads blowback

C

chefman4u2

Inactive
My 45 acp reloads are displaying a black soot mark coming back on the brass. I thought that the crimp might be the issue, so I slowly increased it to the point I know I have a heavy crimp but they are still unchanged. I am firing them out of a Glock 21 and have even switched barrels to see if it was the chamber and it's still the same. Any ideas?
 
What load are you using? Black soot on the outside of brass is usually a sign of low pressure not expanding the brass enough to seal the chamber.
 
Yup, heavy crimping is not recommended or needed for the .45 auto. Back off the crimp untill it's about .001" or .002" less than the diameter of the case over the bullet.

Sounds like your load is too light to seal the brass to the chamber walls during firing, but without the details of your load it's hard to diagnose.
 
chefman4u2,

Welcome to the forum.

A couple of points. Since the 45 Auto is designed to headspace on the case mouth, the mouth diameter of the finished round has a specification to meet. It is to be between 0.467-0.473" wide. You should not crimp it more narrowly than this unless you are seating bullets out to headspace on the bullet instead of on the case mouth (see third from left in illustration below). Many old time (60's and earlier) target shooting competitors actually headspaced on the bullet and put a fairly firm roll crimp into soft lead bullets (swaged). This improved pressure and ignition consistency with light loads and many said they'd found this the most accurate combination.

As others pointed out, soot is a sign of pressure that is low, but it means low for the powder you chose and not necessarily low for the gun. This can happen because the slower burning your powder choice is, the higher the pressure it needs to burn cleanly is. If you are running light loads, choose a fast powder. This way you will be using a smaller charge weight, making adequate peak pressure for the powder choice. Note also that for any given powder charge, the lighter the bullet, the lower the peak pressure, so very light bullets often need very fast powder to burn at all cleanly.

Let us know what your load consists of, and we can offer comments. I'll say, in general, the 45 Auto has such a wide, short powder column that you can get full normal hardball performance using powders no slower than 231, Unique, or Universal. High IPSC power factor +P loadings need slower powders, like Power Pistol, HS6, or Accurate No.5 or 7, but unless you load those kinds of rounds, you are just burning more charge weight and making more recoil and fouling and don't need them. Very light (185 grain and lighter bullet) gallery loads can use powders as fast as Clays and VV N310 and N100 to good effect. Bullseye has long been an old standard in this round. For full power hardball I use Hodgdon Universal because it is cleaner than the other two powders or than Unique, which has a long history in this cartridge, too, but at target load pressures it tends to leave unburned grains behind.

45SeatingPossibilities_zpsea6ec64c.gif
 
Pictures would help. How much soot?

All of these pistols unlock when there is residual pressure in the barrel and some unburnt powder is going to get in the chamber. Residue can be reduced by increasing pressures but that is not necessarily the best solution. A better concern is whether your pistol functions reliably, I consider soot be cosmetic if the load is accurate and pistol function reliable.

And of course, how much soot? These are cases I picked up from the Army Marksmanship shooter next to me. I shot a Bullseye pistol match and some AMU showed up. They were shooting M1911's in the 45ACP stage and shooting factory new Atlanta Arms 185 gr JHP's. Notice the soot and rub marks on the cases? These guys' M1911's functioned fine, shoot little groups, and I would say, soot was not a problem.



 
FWIW, Winchester White Box in 45 ACP 230gn "Ball" blows back quite a bit. And WWB is something of the "benchmark" for your basic range shooters.

I think 45 ACP is prone to blow back - it's a low pressure cartridge. Therefore, I have kind of stopped bothering to notice the blow back quite a few years ago.
 
Thanks

I think you all nailed it. I do know that they are a bit to low on the charge. I've got to modify the powder drop to increase the load. It was stuck with to low or to high with the Lee progressive press....37 is to low and .40 is to high so I used the lower. I'll drill it out to get the right formula. Thanks a million!

FYI...I am loading 230 gr jacketed RN with Titegroup. I want it to drop 4.4 to 4.6, but the .37 is dropping 4.2~4.3 and the .40 is dropping 4.7~4.9 so I've been using the .37....I'll modify the disk.

Since it has been having this blowback, the gun has started having malfunctions. Once I cleaned and lubed it, they went away so it is affecting the functions. The main issue was the slide not closing completely.
 
Last edited:
I agree with Slamfire and Jim. Soot on the case (or in the gun) does not concern me if everything else about the load is good.
 
I get bits of unburned powder and bullet coating flakes when my 45's aren't loaded to max charges. Doesn't matter what powder I use.
 
.37 is to low and .40 is to high so I used the lower. I'll drill it out to get the right formula.
Click to expand...
Drilling a disk may not get you a good result,the charge bar just may do it and
since your issue seems to be low charges the .40 cavity is probably the solution.
 
I see burns like that on lots of rounds, even factory. Hard brass, low pressure,even chamber deviations or powder that's not right for the round acc cause gas to leak before the case month fully locks down.

I figure th a by now you have all of the information you need, tinker around in batches of ten rounds until you find one that you like
 
OP,drilling and tapping a disk cavity is a mickeymouse attempt to get consistent
throws,simply consider before doing it that you will be exposing multiple obstructions in the powder's path that were not there before,who knows? some folks give glowing reviews to the operation results and others don't say anything out of frustration.Your choice of course,I just thought you may want to read about a different take on that topic.
 
The point of drilling and tapping a cavity is to allow a very small, repeatable and slightly adjustable change in the capacity of said cavity. That is entirely different from a goal of simply placing an obstruction in the path of the powder.

Using this technique does have its risks. If you are leaving powder on top of the screw or encountering some other issue, you are likely doing it wrong and probably would want to take a different plan of attack (smaller/larger screw, filed threads, etc), try other powders or move to an adjustable drum measure.
 
Using this technique does have its risks.
Click to expand...
Dispensing risky advice can't be helpful to anyone.The modification in question isn't new,actually Richard Lee comments on it in the First Edition and pointedly
doesn't in the Second.OP has a minor issue and there are a number of simple and safe solutions to resolve it.
 
You must log in or register to reply here.
Back
Top