Sticky bolt

[grit]

While shooting today I had the bolt stick a little. The handle rotated freely, but when I tried to pull it back it stuck. I pulled harder and it came free. I inspected the case, and found a ring indented about .01 from the end of the shell. This was a factory load.

I have a couple hundred once fired cases of this same ammo. I inspected them, and found a similar ring on many.
I next measured them, and found them to be three thousandths over trim length, and well under listed max length.

I've concluded my chamber neck is .01 or so short. I would like second opinions.

 

[Jimm]

Grit,

What are you shooting ? gun/ammo. Is it possible you are talking about the factory crimp ? Describe this " ring " , is it a bright mark on the brass or is it a regular indentation around the case mouth ?

If I understand you correctly you have fired a couple hundred of these with out any problem. You may just need to clean your lug recess , cause you might have some " grit " in there [image]

[/image] Sorry , I couldn't help myself , I mean hunting season is over and i have to wait another year and what am I gonna do /ubbthreads/images/graemlins/blush.gif

Jim B.

 

[royinidaho]

grit,

You didn't say which end of the shell?

I'm supposing that it was on the case mouth end.

Simple test: Take one of the cases that has the ring. Will a bullet drop through the mouth to the bottom. Just fall, no push?

If no, cases are too long. If cases are in spec for length, then something is too short /ubbthreads/images/graemlins/frown.gif

Then try a brand new case that has been chamfered/deburred and full length resized.

Also your once fired cases should be the same cartridge for the chamber. Not something like an 30-06 full lenght resized to a 25-06. There may be an intermediate step that you should be aware of.

 

[grit]

Got me! That was funny.

Ok, the ring I'm seeing is the factory crimp /ubbthreads/images/graemlins/blush.gif. Caliber 270 win. Rifle winchester 70.

Bullet will not drop through once fired case. Loaded factory ammo neck = .305
once fired neck = .308
resized neck = .302

I actually felt a little stick on three or four of twenty. This one stuck hard.

Barrel did not get hot.
No scarfing I can see.
Primer looks the same.
Expansion is the same as others.
Case length is the same.

Only difference I can see is the case mouth is bent, like it buckled in.

It was quite cold. 15 degrees. Maybe the case mouth buckled due to the extreme temp change? Caused out of round and a pinch?

 

[royinidaho]

Ok, I've been there and done that, but don't have the guts to wear the tee shirt /ubbthreads/images/graemlins/grin.gif

When the rifle is fired one of the first things that happens is that the case streches, gets longer. This is even before the bullet leaves the case mouth.

If the case is too long it hits the end of the chamber and folds in uniformily gripping the bullet before it can leave the case. Thus pressure goes up depending on the strength of the grip on the bullet.

Thus the test of, will a bullet drop back through the case mouth after firing.

If the above conditions exist, it is not a safe situation.

Also, from your case measurements, it may be that your chamber is short or the distance from shoulder to end of neck is short on the chamber.

You'll want to figure that out.

BTW, my experience was with a 270 Win and 130 gr bullet also.

But, on the other hand if the neck is buckled it may be a whole different story. By buckling I mean what the shoulder looks like when you put too much lube on when resizing.

If your getting a dimple on the neck that looks something like a small football has been pressed into it, gasses getting back past the case mouth may be indicated. /ubbthreads/images/graemlins/confused.gif With the sticky bolt being due only to the deformed case neck.

If that's the case I'd recommend contacting any of the rifle smiths on the board with the question.

 

[Varmint Hunter]

You got me, but is it possible that the case necks are getting dented on extraction and/or ejection?

 

[grit]

Guts?

A little lite work with the deburring tool allowed bullets to drop in. Tightness was only an hundredth or so.

Dent is like you squished a straw, to put in another straw to make a long straw, to steal your sisters soda. I've seen case mouth dents before. Always attributed them to extraction. Likely as not the case here.

I'll clean 'er up. I've always kept this gun well cleaned. Prior to the days shooting, I cleaned it in the evening. Let it soak over night, and finished in the morning. I use Tetra gun copper solvent. I've noticed on a handgun, the carbon can be stubborn. Is there something more effective for carbon, (carbuerator cleaner?) I should be using in my regular cleanings?

Is it possible my choice of solvent is allowing carbon build up,in the slightly more open neck? I would expect the neck and throat to be cleaned along with the bore. Do they require seperate attention? How do you clean them?

 

[royinidaho]

I doubt its extraction, w/a Mod 70 you'd have to be racking them out pretty hard.

Dented by a tiny foot ball, folded like when one stole sister's soda. Talk about a high tech dialog! The sad part of it is I know whatcha mean. But I'm probably visualizing it larger than it really is. Still may be a leak past the case mouth?????

Anyone perusing this have a pic? I've seen/caused dents in the shoulder due to too much lube and have seen the neck folded in a bit from pressure leak but don't have any examples.

GM Top Engine cleaner. About 7 bucks for a can at the GM parts store. Learned it from this board somewhere. Pretty sweet stuff. Major rapid powder residue removal. Same ingredients as some popular bore cleaner and a bunch less expensive.

I run it through to clean out the powder fouling prior to using Wipeout to get the copper. I don't have the accelerator for the Wipeout so I let it set over night.

 

[grit]

It did come out hard, when it broke loose. Not real hard, but I flipped it behind me, instead of just dropping it in my hand.

The case mouth has two crescent shaped indents, about 1/16". Makes the case mouth look like a clover leaf with the indents blended together. The indents run down the neck a big 1/8".

 

[littletoes]

Im a little confused here, are we talking factory loads, or handloads?
Is there a heavy carbon ring just ahead of the chamber? If so, it can be removed by a little elbow grease and some JB's, but don't get overly aggresive, nor move that rod too fast.

 

[royinidaho]

I'll email a smith and get him on this.

Sounding more and more like "blow by" but in a pattern that is a bit confusing.

 

[bcd]

On my rem 700 chambered in 270 win just about every piece of brass that I have fired has dents around the shoulder neck area, when I started reloading for it I was culling them out but I wound up not having enough brass to mess with, so I bought some new winchester brass.

Out of all my brass the new is the only brass that doesn't have the dents in it, and I'm on my fourth or fifth reload with it.

All of the factory loads were winchester 130 gr soft points or federal premium 130 gr ballistic tips.

All of my reloads are 140 gr nosler ballistic tips in front of 58gr of H4831sc with CCI250 primers and the last 25 or so with 140 gr accubonds. I have loaded about 10 Sierra 90 gr varmiteers,but I discarded that brass.

 

[royinidaho]

Bryan D,

You have a problem......

 

[royinidaho]

grit/Bryan D,

/ubbthreads/images/graemlins/confused.gif There should never be dents in any part of the case either before or after firing. Any dents, dings, splits, grainy looking brass ahead of the web, etc, always indicates a problem of some type.

Here are some examples from the Speer #9 reloading manual. Hope I don't get sued /ubbthreads/images/graemlins/crazy.gif

Results of too much lube:

Freebore and too slow of a powder: