Powder blast in face when firing 1911

I have a new Springfield Arms range officer 45 ACP and have been getting a powder blast in the face when I fire it.  The gun has 200 rounds thru it and has been doing this since round #1.  Since this is my first 1911, I am not sure if it is the gun or the load.  Is this typical for a light load in a 1911? 

Here are some load parameters:
I am using HP 38 powder loaded at 4.4g up to 5.0g.
A friend let me use his chronometer and the velocity at 4.6g was 725fps.
I am using a 200g, Zero brand LSWC.
I am using new starline brass.
My crimp is .470" (if I go smaller the round seats too deep per my check gage)
There is less blast at 5.0g than at 4.6g.
I have tried loading some titegroup and am getting slightly less blast with that powder.

This may or may not have anything to do with the blast in my face but the chamber part of the barrel has a hard caked residue from the blast.  I have not been able to remove it with Hoppe's #9 or KG1 carbon remover.

Any thoughts on what to try next?  (I just received some VV310 that I may try)
DWalker

The brass case has to expand to seal the chamber, which requires a certain pressure level on the load.  If it does not seal the propellant gas escapes rearward past the case (path of least resistance), and in a 1911 type breech there is nothing to contain it within the pistol.  Your hotter loads seal better and prevent this.  That being said I have owned a lot of 45s over the years and have used everything from hot to mouse fart loads and have not noticed this.  It may be a pistol issue, call SA and tell them what is happening and get their take on it.  Even with the light loads I shoot in my RO this is not happening.  I am not sure of the velocity on my loads but often can see the bullet in flight.

Thanks for the quick reply.  So this is not normal.  Thats good to know.  The case not expanding and sealing makes sense.  I see a lot of people using a tighter crimp.  Would that allow the pressure to build higher and possibly seal the chamber?

Is there any soot on the outside of the case and where does it stop along the case wall?

An indicator of low pressure/incomplete brass sealing is if you have a lot of fired cases coming out with a lot of carbon blackening on the outside - the propellant gases are getting between the brass and the chamber wall while the bullet is still traveling in the barrel.

Yes, a tighter crimp ought to hold the bullet a little longer and allow pressures to increase a bit more and let the brass seal the chamber better before the bullet starts to move out of the case. I believe the widely-accepted taper crimp diameter is 0.469".

Use a faster powder, like WST or bullseye, for light loads or increase your current charge of HP38. The above posts are right, the case must expand to seal the chamber. With light charges, a faster burning powder will reach peak pressure faster and cause the case to seal the chamber allowing less blow by. Hodgdon.com has a great powder burn rate chart.

Re: Powder blast in face when firing 1911

 by Wobbley Yesterday at 10:42 pm
Is there any soot on the outside of the case and where does it stop along the case wall?

The outside of the case has soot primarily on one side.  The soot goes about half way down from the case mouth. 
It does sound like the case is not sealing.  I will try the VV310 which is faster than the HP 38 I have been using.

The other thing I am wondering about is my crimp.  Could that be contributing to the problem?  My crimp has a taper at the end of the case mouth that causes the round to seat too far in the case gage.  I have to back off on the crimp to keep the round from being too short. I measure the crimp about 1/16" from the case mouth.  Is that the correct place to measure the crimp?  ( I am using a Lee factory crimp die to make the crimp.)

I check the crimp right at the case mouth. A bit hard to do but once you get the hang of it measuring the case mouth is a breeze.

Sounds like (if you are measuring the crimp 1/16" back from the case mouth) that you are over crimping by a tremendous amount. That's why your reloads are dropping so far into the case gauge to far.  I crimp to .470 right at the case mouth. The way you are doing it you are #1 squeezing the bullet down past the ideal diameter of .451-.452, #2 you had squeezed down the case itself and are getting blow-by because the case is now to small to properly fit the chamber.

Back off your crimp so that it's .470-.469 AT THE CASE MOUTH.


Virgil

Thanks Virgil for your suggestion.   I just measured some dummy rounds that I made when setting up my press.  They were between .466 and .468 at the end of the crimp. 
It appears that over crimping combined with light loads of a slow powder is the cause of my blow back problem. 

Thanks to all for your suggestions.  While I have been shooting for almost 60 years, I am new to the 1911 and reloading 45ACP.  Your help with this problem is appreciated.
DWalker

I'd get that caked up soot out of the chamber too.  The brass can't seal with those variation in there.  Soak it in hoppes, butches etc. and use a wire brush.

Good point.  I will get it soaking today.  I am looking forward to getting to the range next week with some new ammo and a clean barrel!

Virgil Kane wrote:I check the crimp right at the case mouth. A bit hard to do but once you get the hang of it measuring the case mouth is a breeze...

Something I've started doing when measuring the crimp is to set the calipers to the width, i.e. 0.469, and lock the jaws.  Then see how the mouth fits the setting.  I find this easier than trying to adjust the calipers while holding on the mouth.

Ed Hall wrote:

Virgil Kane wrote:I check the crimp right at the case mouth. A bit hard to do but once you get the hang of it measuring the case mouth is a breeze...

Something I've started doing when measuring the crimp is to set the calipers to the width, i.e. 0.469, and lock the jaws.  Then see how the mouth fits the setting.  I find this easier than trying to adjust the calipers while holding on the mouth.

Ed,
Thanks for the tip.  I will give it a try when I adjust my crimp die.
DWalker

Hi DWalker, In addition to the sage advice previously given, here's my advice.

Toss your case gage into some deep recess of your loading equipment; in other

words stop using your case gave ever again.  Only use your pistol's barrel to do

a plunk test for your loaded cartridges. I believe you'll find that most experienced

45acp loaders only check their cartridges using their pistol's barrel for testing potential

functionality of their loaded rounds. This enables tailoring loads to a specific chamber.

Tony

paw080 wrote:Hi DWalker, In addition to the sage advice previously given, here's my advice.

Toss your case gage into some deep recess of your loading equipment; in other

words stop using your case gave ever again.  Only use your pistol's barrel to do

a plunk test for your loaded cartridges. I believe you'll find that most experienced

45acp loaders only check their cartridges using their pistol's barrel for testing potential

functionality of their loaded rounds. This enables tailoring loads to a specific chamber.

Tony

I will be going to the range this morning to try out changes to my loading process that were suggested. 
Regarding your suggestion to use the barrel for a plunk test.   I am very interested in optimizing loads for my gun.  What variables can I change by using my guns barrel rather than my generic case gage?

djw1cav wrote:
I will be going to the range this morning to try out changes to my loading process that were suggested. 
Regarding your suggestion to use the barrel for a plunk test.   I am very interested in optimizing loads for my gun.  What variables can I change by using my guns barrel rather than my generic case gage?

Hello again D Walker, The reason we use the pistol's barrel to check the loaded round's fit;

is because the Case Gauge is manufactured to  SAAMI specifications. While your, mine and most

other barrels deviate a tiny bit from those standards.  Plunk testing with your barrel reveals what

 OAL, seating depth  and Taper crimp dimension will function most reliabley in your particular

 chamber. This means that you can load a round more specific for your pistol than using a case

gauge.

I have a question, What type of shooting are you loading for?  The 1911 RO is a great entry level

Bullseye pistol;  Is that your desired use?  If so, you'll have to check your precision load at 50 yards.

the short line (25yds) loads can be charged much lighter; it is much easier to get X-ring accuracy for

the Timed and Rapid fire target. Good luck with whatever kind of shooting you intend.

Tony






Tony

I have the same issue with my new SA RO. Fired 120 factory rounds and 150 reloads. I dont get blow back on factory ammo , only get it with my reloads and it only occurs every 5or 6 rounds. 

Reloading with CFE Pistol powder. Loaded a batch with 5.2g and 5.6g. Bullet is 230g plated Xtreme. Used Lee reloading data they recommend starting at 6.0g for jacketed and 5.4g for lead. Recoil is definitely softer. When examining the fired cases I am noticing a few with powder burn on one side. So do I crimp or add powder? I am  a new to reloader. Thanks in advance for the help..

My loads are way softer than that in my RO, but there is never blowback getting to my face. The soot on one side of the case is normal.

I had a friend that loved to load light, he had some of the lightest loads possible. One time we were shooting indoors at 50 feet. His bullet bounced off the cardboard we had behind the target frames.  I never seen that problem you describe happen to him! Those stupid light loads had me laughing so much I couldn't shoot!
 What it may be is your gun is not locking up right and opening too early. I don't have my manual handy but you might compare the measured velocity to the velocity the manual indicates for that load you using. If there is a big difference I would begin to start looking at the gun. Crimp and accuracy are combined, I doubt that the crimp will change anything like what your having!

Frank

blow back could be from to light of crimp. A 45 should always be crimped to at least .469 at the case mouth on a .452 bullet and .468 on a fmj that is .451, the crimp gives the round time to build pressure and burn the powder. Many even go tighter, but in hundreds of ransome tests ive found best results with .467-.469 in all types of bullets.