Thread: Understanding Group and measures

@Tentman. Im a bit south of you I think, but I can turn a comparator for your 223 on my lathe pretty eadily if you visit with fired unsized brass . Pm me if you need this.

Misfires are terrible for flinch in one way,but great in another..you sure know if you pulled away... But the not knowing if will go bang is hard on nerves.

Originally Posted by Woody

@Tentman. Im a bit south of you I think, but I can turn a comparator for your 223 on my lathe pretty eadily if you visit with fired unsized brass . Pm me if you need this.

Hey thanks for the offer @Woody, appreciated, but I'm in Invercargill (the southern Vegas haha) and they are readily available for $25 if I cared to order one from Gunworks.

Ha ha, fair enough.

I had misfire issues with a model 7 that was primer fussy I believe it was the cci in my case and fed 205s fixed it white rivers weren’t around when I had that shooter

Originally Posted by Tentman

Yes. The measurements are relative as I don't have the correct shoulder comparator (I using a 0.308 bullet one, it's supposed to be 0.330 for true mid shoulder) but it doesn't "like" brass measuring under 1.496, most factory stuff I have here is about 1.492-1.494, and my old die set up was bumping to 1.493-1.494

I also use a .308 comparator for my .223 headspace measurements for setting the sizing die, I think my die is set to bump to 1.498. From memory.

I might take a few measurements tonight. Doesn't seem like you should be seeing a major issue from headspace with those numbers. I guess, what's a couple of fired cases measure?

Cases fired in the S&L measure 1.495 to 1.497
Cases that misfired measured 1.488 to 1.494

Fired cases from other 223s here measure 1.496 to 1.498

I measured the Go guage at 1.495 and the No Go at 1.501 (measured with the exact same calipher/comparator)

Firing pin protusion measures at 0.583 to 0.060.

Everything looks pretty normal, I don't see any signs of spring or sear drag.

I shot the rifle today with selected "long" Cases at 1.496 and Remmy 7 1/2 primers and still had a FTF. Groups were however much better - it was extremely windy so the ES was a bit higher but there were no huge fliers like I had been getting.

I think the next step is to try a heavier main spring and see what that does. I'm thinking there is an "ignition " issue going on here but it very hard to diagnose with my somewhat random approach (sorry scientists/engineers @gimp et-al!) and in a rifle that is unlikely to ever get to BR levels of precision.

I've been pooh hooed for suggesting this before...but it worked for me. When bolt is out of rifle ,resting in storage,let the spring down by turning rear of bolt so it sits in fired position. My zastava used to misfire a few times until I did this.

I have the universal solution to head space problems
But I won't mention it to avoid sounding like a stuck record !

Those of you that know me will know exactly what I would say .....

Partial length resize perhaps lol.

Originally Posted by akaroa1

I have the universal solution to head space problems
But I won't mention it to avoid sounding like a stuck record !

Those of you that know me will know exactly what I would say .....

Rimmed cartridges in break-action single-shot rifles?

Originally Posted by gimp

Rimmed cartridges in break-action single-shot rifles?

They never faul to go BANG

Originally Posted by Kelton

I had misfire issues with a model 7 that was primer fussy I believe it was the cci in my case and fed 205s fixed it white rivers weren’t around when I had that shooter

I had fail to fires with a Sako AI and sure enough it was the shorter headspace rounds that did it most.
But also I believe it was CCI primers being tougher because it never happened with Federal.
Then there were a couple of instances where the firing pin didnt fall but did as I went to open the bolt !! This was after a wet weekend and perhaps a bit of rust or debris was contributing.
A fault was found with a broken pin in the trigger assembly.

So a combination of minor issues gave a difficult to solve problem and wasnt just “fix this and it goes away forever”.
It seems to have been OK for a while now.

Originally Posted by gimp

Rimmed cartridges in break-action single-shot rifles?

Rimmed cartridges "per se"

Falling block, rolling block or break action. I'm not that fussy

Originally Posted by Bagheera

I had fail to fires with a Sako AI and sure enough it was the shorter headspace rounds that did it most.
But also I believe it was CCI primers being tougher because it never happened with Federal.
Then there were a couple of instances where the firing pin didnt fall but did as I went to open the bolt !! This was after a wet weekend and perhaps a bit of rust or debris was contributing.
A fault was found with a broken pin in the trigger assembly.

So a combination of minor issues gave a difficult to solve problem and wasnt just “fix this and it goes away forever”.
It seems to have been OK for a while now.

The WRE primers have seemed to exacerbate the issue, perhaps they a bit harder than the Federal 205s and Remmington 7 1\2s. But it's never that simple huh!