pressure

vetrider

why is it that on my .223 reloads, 1 out of 5 show signs of pressure? the primers are flattened, the other four are in perfect shape. i am using 55 gr. fmj in federal cases with winchester small rifleprimers with varget powder at 27.2 grs. this is close to max charge but still .5grs away. there is no other signs but the primer.what gives? i can load at 26.8 grs and the primers stay put . am i running so close to the edge that a few rounds will show signs or what. i would like to keep the charge at 27.2 as this seems to be the most accurate, more so than the 26.8. i guess it really doesn't make a lot of diffence but it sure seems noticable, maybe it is just in my head.

JustC

What is the interval between your rounds? Which round in let's say a 5rnd group usually shows the pressure sign? Or have you checked? I would bet,..that if the other rounds don't show pressure,..your flat primer case is the last round fired in the group. I have had loads that would shoot great,..and show slightly higher pressure as the shot string increased. My theory is the heat in the chamber and a more temp sensitive powder lead to this result.

why chase the game when the bullet can get em from here?....
Got Balistics?

vetrider

i never thought to see when it happens, just noticed that out of every group there is one thats flattened. never dawned on me that a pattern is developing. i will have to pay more attention to that next time out.

brimickri

The barrel will start to consrict with heat causing more friction, which causes more pressure in the chamber. So, take a marker and number a bunch of rounds and shoot them in order and you will mostly likely see more and more pressure distortion with each followup shot. A good friend of mine was out on the range today, shot 50 rounds, and after loading a new mag. the gun left go! The upper receiver on the AR-15 blew apart, and destroyed it. It blew the mag out of the receiver, flattened the next round just about flat, and dropped all the rounds on the ground, needless to say , it's now garbage. We are gonna try to see what happened, but in either case, he is contacting Olympic arms to see if they want it. That makes you think about loading "hot" loads. The load he shoots is pretty tame, and he's never had a problem before. Luckily, all he got out of it is one mother of a headache!!

temblor

Are you by chance letting a round sit in the hot chamber for awhile before you shoot? Sometimes if you let one cook in the chamber like that it will cause things like that...........[8D]

perry shooter

LOOK FOR OAL OF EMPTY CASE IF YOU ARE RELOADING. IF YOUR DIES ARE ADJUSTED JUST SLIGHTLY SHORTER THEN CHAMBER OF RIFLE THIS WILL SET THE SHOULDER BACK & AND MAKE THE NECK LONGER .THIS LONGER NECK CAN SOMETIME JAM INTO THE LEAD OF RIFLEING AND SQUEEZE THE BULLET SO HARD IT CAUSES HIGH PRESSURE ON FIREING

asphalt cowboy

Are your cases sorted by lot number or mixed? One lot number may have a thicker case head than another.
Trim to length and weigh them on your powder scale, sort by weight.
I count angels with a 264 Win Mag and .5gr can give outragouse pressure signs with a heavy case head, made that mistake only once and learned from it.

CountryGunsmith

I've always been in favor of the simplest things first. If you are weighing your powder charges and are 1/2gr shy of book maximum, I am doubting you are creating excess pressure. I would be more willing to bet that you have an occasional high primer.

Also, barrels do not constrict with heat. Metal expands with heat.

vetrider

the cases i have been using are federal. i am assuming that they are military rounds as the primers are crimped in. i got a crimp remover and used it on the primer pockets. i was told that mil. spec. cases are a little thicker and be careful on increasing charges. just seems odd that only a few show signs.

FrancF

quote:small rifleprimers

Just a note (Just in case) if you happen to be using Mag primers
subtract .5grs. Belive it or not, shooting with them on a cold morning
you my not notice. Use the same load on a hot afternoon and you will se a diff.

stalion10

they all may not so the signs on the very first reload, but will after a couple, so that could be the problem, the fact that you are experiencing excessive pressure even on 1 out of 5 should tell you to back off. either that or make sure your health and life insurance is up to date. if you don't want to back off let me know, I'd like to take out a policy on you, heck I'd pay all the premiums and split it with you survivors even if you'll let my. let it never be said that i wont invest in a sure thing quote:Originally posted by vetrider
the cases i have been using are federal. i am assuming that they are military rounds as the primers are crimped in. i got a crimp remover and used it on the primer pockets. i was told that mil. spec. cases are a little thicker and be careful on increasing charges. just seems odd that only a few show signs.


it's not the type of gun you have in the heat of a battle that counts, only if you have enough ammo for it, lets face it, a gun without ammo is only as good as a base ball bat!!

Xracer

I'm not sure that this is a pressure problem. First place I'd look is to the primer and primer pocket.

It could be that every once in a while you're not seating a primer deeply enough....or...some of your brass could have a slightly enlarged primer pocket, allowing the primer to "blow back" on firing.

I like to load my primers with a hand "squeeze-type" primer seater. That way I can feel any enlarged primer pockets. Then I run a straight edge (machinist's ruler) over the base to check for "high primers".