Brass Won't Chamber - Perplexed

[copperking81]

I'm having issues chambering resized brass out of my pre-64 M70 .220 Swift and cannot narrow down the cause.

I had reloaded once fired Hornady brass and noticed while at the range, some of them would not chamber in my M70. I figured I didn't have my FL sizing die turned down far enough. I did fire the rounds out of another .220 Swift later. I then cleaned the brass, ran a few through the FL sizing die, measured headspace with a comparator, and proceeded to test. They would not chamber. I then incrementally started to turn the die down to the point where I can no longer turn it down and still get cam over. Still will not chamber.

Fortunately, I was able to find a piece brass that was 1x fired and would chamber easily in the rifle. I proceeded to take measurements of that case and the other cases I had used to test that would not chamber.

Good Case

• Headspace = 1.728
• Case length = 2.196
• Case width at base= 0.442
• Case width at mid point = 0.425
• Case width just below neck = 0.405

Bad case

• Headspace = Started at 1.728, took it all the way down to 1.722
• Case length = 2.196
• Case width at base= 0.440
• Case width at mid point = 0.425
• Case width just below neck = 0.404

In every way I measured, it seems the bad case is smaller so I cannot figure out why it won't chamber but the other case will.

I'm guessing it might have something to do with the brass having been fired out of two different rifles but considering all the brass went through the FL die anyway, I'd think it would get it consistent. Both the good and bad cases all chamber in the other rifle, which is a Ruger No1.

What am I missing!?!?

 

[dolek]

Can you see on the brass just how far the sizing die has made contact ?

 

[Plumsask]

I wonder if the chamber was cut with a worn reamer and is now a very tight chamber. I had a savage 338 that had the same symptoms.

 

[243winxb]

Oval chamber or bolt face not square to chamber?

New Gun = New Brass

 

[Mikemci]

This sounds like an impossibility.
Brass of smaller dimension won't fit in a chamber. Brass of a larger dimension fits. Somthing bout these measurements aint right.

 

[J F Johannes]

Neck diameter?

Jim

 

[WillyTP]

Color a bad piece of brass all over with a sharpie, try to chamber it and hopefully it will show where the problem lies.

 

[copperking81]

Color a bad piece of brass all over with a sharpie, try to chamber it and hopefully it will show where the problem lies.

I tried that but not all the way down the brass. I'll try that.

 

[copperking81]

Neck diameter?

Jim

Consistent between the two.

 

[hogpatrol]

This is a problem that pops up periodically, brass fired in one rifle and even after resizing won't fire in another rifle. Solution? Stick with brass shot in each individual rifle.

 

[rammac]

Good Case

• Headspace = 1.728
• Case length = 2.196
• Case width at base= 0.442
• Case width at mid point = 0.425
• Case width just below neck = 0.405

Bad case

• Headspace = Started at 1.728, took it all the way down to 1.722
• Case length = 2.196
• Case width at base= 0.440
• Case width at mid point = 0.425
• Case width just below neck = 0.404

Hmm, SAAMI specs say that the diameter at the base of the case should be .4449", I wonder how your case is so much smaller.
SAAMI headspace is 1.803" to 1.810", and yours is .075" to .082" shorter?

Something isn't right, I don't have any idea how you could get so much shorter headspace after firing the case, a couple of thousandths shorter I might but I've never seen a case end up 75 to 82 thousandths shorter. The same with case base diameter, the case will expand to fill the chamber diameter which should be .4458" and then shrink a few thousandths as it cools off but your case is close to 6 thousandths smaller in diameter.

 

[copperking81]

Hmm, SAAMI specs say that the diameter at the base of the case should be .4449", I wonder how your case is so much smaller.
SAAMI headspace is 1.803" to 1.810", and yours is .075" to .082" shorter?

Something isn't right, I don't have any idea how you could get so much shorter headspace after firing the case, a couple of thousandths shorter I might but I've never seen a case end up 75 to 82 thousandths shorter. The same with case base diameter, the case will expand to fill the chamber diameter which should be .4458" and then shrink a few thousandths as it cools off but your case is close to 6 thousandths smaller in diameter.

Where on the base is that measurement? Its a rimmed case so if you're talking about the rim, that might be it. The measurement I listed was not at the rim but just above it. It's possible I misread the caliper too.

As to the headspace, I'm using a Sinclair 21 degree bump gauge to measure, as in the link below. I can't explain why I'm getting the measurement I'm getting.

https://www.sinclairintl.com/reload...ools/sinclair-bump-gage-insert-prod35265.aspx

 

[copperking81]

Attached is a photo of a marked up case. This case will chamber but you have to set out to do it. It was very stiff but with brute force, I could get it. I did it a few times.

It's hard to see but the red box in the picture is where I see some contact. It doesn't appear there is any at the shoulder or neck... nor the first ~1/4 of the way down from the shoulder. It's almost as if it's bulging just a smidge around the "love handles" area...if that makes sense.

 

[copperking81]

This sounds like an impossibility.
Brass of smaller dimension won't fit in a chamber. Brass of a larger dimension fits. Somthing bout these measurements aint right.

Trust me... I know. I've taken the measurements multiple times and yes it doesn't make sense. This isn't the first time I've had to work to get brass to chamber but I always found the problem. Somewhere on these cases, something isn't consistent.

 

[Martin52]

Where on the base is that measurement? I

This diagram may assist.

https://sierrabulletsblog.com/2016/07/20/a-closer-look-at-the-220-swift/

 

[rammac]

Where on the base is that measurement? Its a rimmed case so if you're talking about the rim, that might be it. The measurement I listed was not at the rim but just above it. It's possible I misread the caliper too.

As to the headspace, I'm using a Sinclair 21 degree bump gauge to measure, as in the link below. I can't explain why I'm getting the measurement I'm getting.

https://www.sinclairintl.com/reload...ools/sinclair-bump-gage-insert-prod35265.aspx

The base diameter is measured about .200" above the base according to SAAMI.

 

[J F Johannes]

I think I see a bulge, look just outside the red box, top right, in your picture. It could just be an optical illusion. Just brain storming here.

Jim

 

[josebd]

I had bought a 22-250 shilen barrel,brand new,and had to use a full length small base die,tight chamber

 

[jds holler]

This aint a first for me. Seen it before, and at that part of the case body.

I'd almost bet that if you could chamber and fire that case, it would fit the chamber afterwards. -- the magic of shrink-back.

I had that problem with my 22BR, with Lapua brass. After I used a small base die just one time, they fit fine afterward even with no more small base treatment. jd

 

[WillyTP]

This might help, measure at .147” from case base and compare that to the print. I think one of the rifles had a little bit big chamber and the Ruger #1 is on the small side.