while shooting AR yesterday I shot some ?match? ammo and noticed burn't powder residue,felt a little oily on brass all the way to web!this ammo was shot in middle of shooting 2 other brands.any ideas out there?
powder burn on entire brass
- Thread starter doc gordon
- Start date
normally when the case is burnt / black from powder burn this means the case didn't expand and form to the chamber and thus left room for the powder burning to move in-between the case and the chamber. I have found that it is normally present when shooting to light of a load or the powder is too slow on burn rate. a case that has more pressure will blow the brass out enough to give a tight fit in the chamber while the round is going off and seal off the chamber area to not let any of the gases back to into the chamber area. hope I explained this where one can understand it
Another issue with AR's is the gas system and buffer . If overgassed it can start the ejection cycle early and this does not give enough time for the gas pressure to come down. It then basically pulls the shell early while pressure is high and breaks the seal. It can show ejector marks from turning the bolt head to unlock while pressure is on the case head.
An adjustable gas system, tubbs carrier weight system, or a heavy buffer will do the trick.
An adjustable gas system, tubbs carrier weight system, or a heavy buffer will do the trick.
jonbearman
I live in new york state,how unfortunate !
If it was oily ,then it had sizing lube on them or the chamber itself might of had oil on it from cleaning which is also a no no .
jonbearman said:
This would be my initial thought ^
RMulhern said:
That's funny right there. Been shootin' too many BPCR's no doubt. Do more than my fair share of them too (BPCR).
The AR's can be a pain, that's for sure. I kinda got lucky with mine as they are not too temperamental. My WAG is the load is not hot enough, but there can be a few reasons for this as was already pointed out.
How about supply a little more info on the load/rifle so we can make a better call.
the oil in the chamber got my attention. for years i used store bought oils to coat my bores after cleaning. stand the rifle muzzel up and put in safe. after awhile i'd go to the range and shoot and on occasion have some early shooting elevated pressure signs. finally checked the chamber before shooting and there was oil everywhere, including the bolt face! factory oils are usually very thin and will run, esp when warm. starting making my own oil with a recipe found on this forum...automatic transmission fluid, 10w-30 synthetic and stp oil treatment. some add kroil and marvel's mystery oil. mix to a thickness that will not run and i'v not seen a drop in a chamber or bolt face. read here that most ars like to run wet and when using the old oil, the first few rounds had the gun smoking...not with the homemade stuff.
Minesweeper3433
45B/91F
I get this same effect on all my semiauto rifles that I run suppressed as well. Just pointing out another cause. My 6.5 swede does this a lot when I run gallery loads as well.
broncman said:
+1 ...very good thought...i had not given that any thought being in an AR...but i can see where that could definately happen...
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