.308 Winchester - Stuck Case

[Texas4x4hoe]

Going to be a little long winded but here goes. So I'm working up a load for my Savage FP-SR 16" bbl in .308 Win. I'm working with some of the 178gr Hornady ELD-X. I have some MKE head stamped 7.62 NATO brass and so far in reading, the start loads are about the same with a reduced max for 7.62. So I started with 35.0 grains of Varget with the bullet seated 0.025" off of the lands and it was 2087 fps and the case stuck in the chamber. The Hornady manual shows speeds for a 22" bbl so my 16" barrel shouldn't be that close to 2100 for the 35gr load I wouldn't think. Could this just be because the case capacity is so much smaller? Not sure where to go from here.

 

[grandpawj]

I'm gonna step out on a limb here and suggest it is a case sizing issue. I am, by no means, an expert. I am sure, Someone will be by with a more exact suggestion as how to solve your sticking case in the chamber.

 

[Texas4x4hoe]

I guess it could be. I'm using RCBS dies I purchased new. This is the first supersonic loads I've done with this rifle and dies. Up to now I had been working on sub sonic loads. They all functioned properly, that said there a lot less pressure in those loads.

 

[kingmt]

Are you sure your that far off the lands? Load one .002" off the lands & smoke it with a sharpy to see if your actually off.

 

[Bart B.]

I don't think it's a good idea to shoot powder charges more than 10% below max. Strange things can happen. Fired cases don't fill the chamber and incipient case head separation starts when they're reloaded.

 

[243winxb]

case stuck in the chamber.

Need more info on "stuck". You fired the round and there was hard bolt lift to extract the case?

Or you could not open the bolt?

 

[Texas4x4hoe]

Need more info on "stuck". You fired the round and there was hard bolt lift to extract the case?

Or you could not open the bolt?

The bolt was tight to lift and it would not open to the rear. Had to tap the case out from the muzzle end.

Are you sure your that far off the lands? Load one .002" off the lands & smoke it with a sharpy to see if your actually off.

Haven't tried the sharpie trick on a loaded round. I've checked with a fired case dented in to hold the bullet tight. Left a bullet out long and chambered it and measure with a bullet comparator on my calipers. The I set them back .025" from there.

 

[243winxb]

Has factory ammo been fired without problems?

Brass- i would check its weight and volume and compare to Rem or Win. brands.
The low pressure sub rounds can make the brass shorter, head to datum. The hotter starting load would stretch the brass to better fit the chamber. May have an effect?

The velocity seems ok to me.

 

[243winxb]

Whats your COL? Hornady wants 2.800"

I am thinking a brass problem.

Hornady's Bullet-When i look at Hodgdon data , using Varget powder, this bullet waves a red flag to me. Strange and different. Compare starting loads at Hodgdon for all bullet weights/types.

 

[Texas4x4hoe]

Has factory ammo been fired without problems?

Brass- i would check its weight and volume and compare to Rem or Win. brands.
The low pressure sub rounds can make the brass shorter, head to datum. The hotter starting load would stretch the brass to better fit the chamber. May have an effect?

The velocity seems ok to me.

Yes I have fired a several different factory full power loads without problems. This particular brass was new loaded ammo and was fired without issues. The brass I'm having trouble with has not been loaded as subs, it was factory ZQ1 ammo and I sized trimmed and de-burred.
I'll check the case weights and compare them.

 

[kingmt]

Can you add a picture of the case head with primer?

 

[Texas4x4hoe]

Whats your COL? Hornady wants 2.800"

I am thinking a brass problem.

Hornady's Bullet-When i look at Hodgdon data , using Varget powder, this bullet waves a red flag to me. Strange and different. Compare starting loads at Hodgdon for all bullet weights/types.

I'm at about 2.820" however I'm am positive that I'm 0.025-0.030" back from the lands.
In the Hornady manual the VLD-X is very close in charge weights to their other 178 class bullets.

Can you add a picture of the case head with primer?

Ok. I was mistaken. These got loaded with CBC 12 cases.

 

[Texas4x4hoe]

I have a few hornady cases resized and ready to load I think I will try one of those and see what the results are.

 

[243winxb]

Online, its been said some Varget lots are faster than others??

But i am guessing a brass problem?

 

[NeuseRvrRat]

how did you weigh/dispense your powder charges?

 

[Texas4x4hoe]

Online, its been said some Varget lots are faster than others??

But i am guessing a brass problem?

That's what I'm leaning towards. We'll see tomorrow with some of the hornady cases.

how did you weigh/dispense your powder charges?

RCBS uniflow and a Dillon scale.

 

[macgrumpy]

Brass problem, check the case head to shoulder dimension and the trim-to-length. I suspect that your trim-to-length is too long and that the case mouth is being forced in to the lands, if that's so then that's part of the reason why you are getting higher speeds than you (and I) expect. The powder charge is less than I'd use, I'd push it up to 36 - 39 grains of Varget.

 

[Bart B.]

The lands are typically a couple tenths inch forward of the case mouth when the rounds are fired. And the freebore diameter between chamber mouth and the rifling origin is much smaller than loaded round neck diameter. So the rifling ever touches the case.

A case too long for the chamber can have its mouth crimped into the bullet by the angled chamber mouth. That's why SAAMI specs allow for about .010" mouth clearance to the chamber neck's end.

 

[The Bushmaster]

Hummm. Was that one of the cases that stuck in the chamber? If so, how come it shows no expansion near the case head that a fired case would have? Other then the primer (that looks normal) it shows no indication that it was fired. Should has some ballooning of the case after being fired.

 

[Bart B.]

I see a faint line about 1/10th inch from the extractor groove. Some fired cases have that at the thicker part; opposite at the thinner part, there's a more pronounced ridge easier to see.

Here's one of my cases showing both sides; left picture shows the thick side.

 

[Nature Boy]

I have some MKE head stamped 7.62 NATO brass and so far in reading, the start loads are about the same with a reduced max for 7.62

I think I understand you to say you did not use MKE brass as your original post indicates, however, I'll make this comment nonetheless. MKE (made in Turkey, branded as ZQ1) is not NATO brass as far as I know. Its case volume is quite a bit larger than everything I've measured using H20. That might factor into your decision when choosing a starting point. Here's what I got in gn of H2O:

LC 14 NATO(Fed XM80) - 54.0gn
FC 7.62 M1A (Federal OTM) - 54.9gn
FC 308 ( Federal Gold Medal Match) - 56.4
Winchester 308 (Winchester 168 Match) - 56.8gn
Hornady 308 (Hornady 168 AMAX) - 56.8gn
MKE 14 (ZQ1 7.62 Turkey) - 57.3

I have a bunch of it that I got cheap from Wally World on their Rollback deal for under $10/box. It's so crappy I've not shot any more of it. I've also not reloaded the cases. I'll try them one day but I've read they're very soft and don't last long.

 

[Bart B.]

We're all those cases' outside dimensions the same?

If not, I don't think your numbers are good.

The only time I've done volume measures on 308 cases was when they were all the way in a full length sizing die so outside dimensions were fixed and just the inside ones changed.

 

[macgrumpy]

The lands are typically a couple tenths inch forward of the case mouth when the rounds are fired. And the freebore diameter between chamber mouth and the rifling origin is much smaller than loaded round neck diameter. So the rifling ever touches the case.

A case too long for the chamber can have its mouth crimped into the bullet by the angled chamber mouth. That's why SAAMI specs allow for about .010" mouth clearance to the chamber neck's end.

Actually your post pretty much says what I wanted to say, I used the lands as a reference because I was in a hurry and didn't want to discuss lead, throat, lands, etc. but I found a drawing that pretty much explains the parts of the chamber that I'm referring to.

My point is that if the neck is too long it can jam in to the short tapered area just before the freebore area. On some weapons (especially some military rifles that can have very short freebore areas), as you point out, a long case isn't safe because the case mouth will contact the freebore area and become crimped around the bullet and raise pressures. This also increases muzzle velocities. I do agree that it would be pretty difficult to do though since the case would have to be over 2.025" long (that built in .010" that you mentioned) according to SAAMI standards but we all know that short chambers have been sold to the public so is it possible that the chamber wasn't reamed deep enough? Maybe the chamber was reamed a few thousandths of an inch short and then fouling is adding to the problem?

 

[Bart B.]

OK, now I'm with you.

Industry standards says that leade section in the picture can also be called the throat. The freebore part in the picture is just that; not part of the throat at all. 'Tis another issue of different names used for the same things across us folks.

 

[243winxb]

The brass I'm having trouble with has not been loaded as subs, it was factory ZQ1 ammo and I sized trimmed and de-burred .

Macgrumpy,
Trim length would seem to be OK. But there seemed to be a mix up** in the brand of brass??