308 re-sizing issues HELP!

7

7887mm08

Member
This will be long so please bear with me.
I m reloading for a tikka t3,using rcbs full length dies. Brass im using is all rem brass that has been fired from several different rifles. I have reloaded for this rifle before but always using NEW rem or lapua brass, never any issues.
Using a Sinclair bump gauge comparator and checking ONCE FIRED BRASS FROM THIS TIKKA I come up with a measurement of 2.680"
I proceeded to size the brass down to 2.677" (.003" bump)
Trimmed all cases to min length of 2.005", deburred inside and out of case neck. I sized 70 cases and loaded 20, using a load that I have already shot in this rifle but with New rem brass.
So go to the range and half would not chamber! Bolt will go all the way forward but would not go down to the closed position. What the heck! Went home and started measuring. pulled the remaining bullets and checked the shoulder length and over-all length, every thing mic's GOOD. Took all 70 cases and tried to chamber everyone, 35 would not chamber. I said well I will resize them again and go .002" smaller for a total of .005" bump
Guess what, most of these still would not chamber. I ended up sizing them down to 2.673" to get them were they would chamber. That's .007" bump from a case fired in this gun. WHY WHY WHY?
A little more info new lapua brass measures 2.671" and new rem measures 2.673". What am I missing here? Im convinced the issue is the brass but where? I do use the dies for a different gun using used brass and I have never run into this. Can anyone offer some insight to what's happening?
THANKS
Gary
 
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Color a non fitting case with a black sharpie and try to chamber it... then look at the brass and see where the marker is rubbed off... likely will be more towards the case head where the die doesn't size it...
 
Just tried it several times on 3 different cases that wont chamber and NO signs of contact any where on the cases!
 
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Originally Posted By: Stu Farishhow long is the brass, case head to neck mouth, vs brass that will chamber?

the same +- .001. Maybe I mis-spoke are you talking overall case length, or something else?
All cases were trimmed after sizing +- .oo1"
 
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Quote:Guess what, most of these still would not chamber. I ended up sizing them down to 2.673" to get them were they would chamber. That's .007" bump from a case fired in this gun. WHY WHY WHY?
A little more info new lapua brass measures 2.671" and new rem measures 2.673".do remington cases chamber? What am I missing here? Im convinced the issue is the brass but where? I do use the dies for a different gun using used brass and I have never run into this. Can anyone offer some insight to what's happening?
THANKS

Will new Remington case chamber?


If Lapua brass chambers @ 2.671" sounds like your chamber is 2.671". Are you sure of your fired case measurement?

Push bolt down a little harder to see if you can get your colored cases to mark. I prefer sight black as sometimes markers are a bit difficult to scuff??

Are you trying to chamber the empty sized cases or are you reloading cases and then trying to chamber? If resized empty cases will chamber but reloaded rounds will not that could be an ENTIRELY DIFFERENT PROBLEM.

Regards,
hm
 
Originally Posted By: hm1996Quote:Guess what, most of these still would not chamber. I ended up sizing them down to 2.673" to get them were they would chamber. That's .007" bump from a case fired in this gun. WHY WHY WHY?
A little more info new lapua brass measures 2.671" and new rem measures 2.673".do remington cases chamber? What am I missing here? Im convinced the issue is the brass but where? I do use the dies for a different gun using used brass and I have never run into this. Can anyone offer some insight to what's happening?
THANKS

Will new Remington case chamber?


If Lapua brass chambers @ 2.671" sounds like your chamber is 2.671". Are you sure of your fired case measurement?

Push bolt down a little harder to see if you can get your colored cases to mark. I prefer sight black as sometimes markers are a bit difficult to scuff??

Are you trying to chamber the empty sized cases or are you reloading cases and then trying to chamber? If resized empty cases will chamber but reloaded rounds will not that could be an ENTIRELY DIFFERENT PROBLEM.

Regards,
hm


yes new rem will chamber and yes I am sure of my measurements. Fired brass from this gun measures 2.680" I had to size down to 2.673 as stated to get the ones that would not chamber to chamber. I did not mention but the 35 that did chamber were sized to 2.677" I am perplexed to say the least. I am thinking that the brass that would not chamber came from a gun that had serious chamber issues and im seeing the results from it. I think the problem is the taper on the shoulder, because that's the only thing I cant compare or measure. Of course my measurements are taken with the comparator on my dial caliper and I am not zeroing the dial, just making comparisons.
 
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This started out with 20 loaded rds in which half would not chamber then I tried chambering the 50 remaining cases which were not loaded and half of those would not chamber.
 
I would bet it's the base of the case like Cinch said. Not uncommon, my bet is your Tikka has a nice tight chamber, while whatever the used brass was from does not. I've run into this before. A small base die should fix your issue if you want to use that brass.

The first time was when I rebarreled my 270 Wby mag. Some of the well used brass from the factory barrel would not chamber in the nicely reamed custom. That was a tough pill since that brass is a little pricey.

Second time was a bhw 20 practical. Since I use once-fired 223 brass to form, I found some wouldn't chamber. A small base die cured it. New brass wouldn't have been an issue.
 
204 you could very well be right. I am not going to use the brass. These were only going to be plinking rounds for my son. I have plenty more brass. just something I have never seen or heard of before.
 
Hi 7887,

Did you take any measurements on the fired brass cartridges that did chamber?

I suppose if you have only shot brand new cases, and never once fired brass, it could be you have a tiny chamber a need a small base die?

On another note. As brass gets worked/fired it "springs back" (resists sizing) shoulder and body.

If your die is set up to bump new Lapua brass back .003, on your 5th firing you may notice it only sets the shoulder back .002.

Add in slightly different brass alloys from different brass makers and a .003 bump could be a different number on a different piece of brass. You basically have to size it back .006 to get it to "spring back" to.003

Math is math though. If you indeed sized it back to 2.677. (then checked it) And that is the correct number for a .003 shoulder bump, then it seems the body is hanging up or you are jamming the lands.

This does not seem like land jamming to me though because you likely would have de-capped one on the ejection cycle and spilled powder all over.

Your chamber is nice and clean right?

Interesting story here!
 
You stated the brass was 2.680? .308 Win brass trim length is 2.006, fired brass maybe, at most 0.010 longer and needing a trim. So, call me confused. OAL of loaded rounds are 2.80 ish.

Must be a typo eh? You must have some cases fired in one serious out spec chamber or a machine gun
 
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A standard SAAMI go gauge for the 308win measures 1.630" this figure is also known as "minimum chamber length". If memory serves me right the datum line diameter used for the 308 is .400", so it sounds like your comparator has a smaller datum diameter. This is not really an issue, it can be anything as long as you have a starting point to zero it. Since it sounds like you are just using fired vs. unfired cases to set a starting point or zero that is okay too as long as the unfired cases are right. Something has to be amiss here as you seem to have too much difference between what fired cases measure and what you have to bump them back to get the sized cases to chamber. If in fact the sized cases must have their shoulder bumped back .007-.008" to be able to chamber AND IT REALLY IS THE SHOULDER THAT WAS STOPPING IT then you have an excessive headspace problem and need the rifle checked by a competent gunsmith. If this is the case do not shoot it, that rifle should not be considered safe.
If you have to resize the fired cases so much that it takes .007" bump to get the case sides small enough to fit, then again, you have a chamber problem. Let me ask this...standard dies wont bump a shoulder back that much unless the shell holder or the die itself has been modified to do so. Have you modified either one??? If not then how can you be "bumping" back further than what a standard resize die will bump??? There is something definitely amiss here, if a small base die will size a case to fit then you have to have either a small chamber or a bad full length resize die.
Definitely have that headspace checked.
 
I will try to answer. I only have to bump the shoulders back .007" on cases NOT FIRED IN THIS RIFLE.
Cases fired in this rifle I bump .003" and they chamber FINE. The issue is with cases THAT WERE PREVIOUSLY FIRED IN AN UNKNOWN GUN. Defiantly not jamming the lands because I am chambering unloaded cases.
No Stu, this is one of the few calibers I load for that I don't have a case gauge.
 
I did clean this rifle real well as our deer season just ended a week ago. Is the chamber clean? yeah best I can tell; Like I said to start, the problem is with just the brass that was fired In an unknown rifle, Brass fired from this rifle sized and chambered fine. A bunch of other calibers I load for i have used unknown brass and never had issues so this issue is new and perplexing to say the least. I only am talking about 75 pcs of brass and its no big loss to toss them.
I REALLY APPRECIATE THE FEED BACK
THANKS
Gary
 
Gary, throw the brass away that was fired in another rifle. Use only Remington brass that you started off new.

Huge difference in Rem and Lapua brass dimensions, Lapua is much larger, set that brass aside for now.


I fear that you have a brass bristle or something stuck in your chamber or a load of brass build up on your bolt face, you have to check those things out.

Do you have a decent tool to clean out the chamber well?

Range pick up brass needs to be sized with a small base sizer, but it is good thinking to start off with new brass in a new chamber or new gun. What if the range pick up brass was fired in an AR 10 or other military weapon with a HUGE chamber.

You are measuring the length, and you have to consider the Web dimension to the .0001. Often to get the web dimension to where the chamber likes it, you may have to bump the shoulder back .011....another set of problems.

Big lesson here for you, throw away the brass with an unknown history. Even if you use a small base sizer and get the brass serviceable, you still need to keep that brass segregated as brass swells back out over time.
 
it's a good stumper. I guess if it were me, I'd take the calipers to the brass & start comparing brass that works with brass that doesn't. The web, mid-body, just under the shoulder and across the neck & see how they spec out.
 


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