Gunsmithing Head space question

[westcoasteast]

I picked up a used vector action, and then a low round count barrel for the vector cut for hand tight/set screw. I hand tightened the barrel, torqued set screws and ordered gauges. The no go gauge is only one that has showed up. The bolt will NOT close on the no go gauge. The bolt WILL close on factory ammo, not as easily as freely cycling bolt, but a little pressure and it drops down and locks up all the way. Cases look fine when I eject them. Any concerns with firing the rifle before the go gauge comes in?

 

[...]

Assuming your ammo is in spec....eh ide shoot it.

The main concern is excessive headspace.....if it doesn't close on a no-go it should be fine

 

[whatsupdoc]

If the caliber is clearly marked on the barrel, the bolt will not close on a nogo and a factory round will chamber without issue you
should be fine.

 

[Steel head]

Shoot it!!!!!!

 

[westcoasteast]

Thanks all!

 

[Wannashootit]

Ditto...
You could save yourself some coin next time, and just order the go gage.
We're usually not concerned with how close the rifle is to being unsafe to shoot (which is what the no-go does).
Confirm first with the go gage, then add/trim a piece of cellophane packing tape to the back. Adds about .003, bolt handle shouldn't fall.

 

[smoothy8500]

The bolt WILL close on factory ammo, not as easily as freely cycling bolt, but a little pressure

Factory rounds are usually .002-.004" shorter than a GO gauge. Sounds like it's even tighter than the factory spec ammo.

 

[westcoasteast]

Factory rounds are usually .002-.004" shorter than a GO gauge. Sounds like it's even tighter than the factory spec ammo.

Educate me...what does that mean or what should it tell me? Is it bad? Will loading form fired brass make it better or is it more an issue of bullet seating?

 

[spife7980]

Educate me...what does that mean or what should it tell me? Is it bad? Will loading form fired brass make it better or is it more an issue of bullet seating?

That means that a go gauge is longer than factory ammo, the factory ammo has to fit in the somewhat larger chamber so the factory ammo has to be shorter and alone won’t be the best way to tell if case headspace is in or out of spec.

What you could do is add a layer of scotch tape to the back of the factory ammo as mentioned above and with a razor trim off any excess overlap. Then just do additional layers until it does fail to close and measure that difference to find out how much longer your chamber is than the ammo.

 

[spife7980]

Oh, and to answer the other questions. It’s neither good nor bad, it just depends. If you’re reloading then you will set your die for the fired brass to the initial size doesn’t really matter. So long as it’s not tooo long of an initial stretch.

Headspace has nil to do with bullet seating. Headspace is the case shoulder to the chamber shoulder.
Bullet seating is the bullet to the rifling. It’s different items to different parts of the chamber.

 

[Threadcutter308]

I picked up a used vector action, and then a low round count barrel for the vector cut for hand tight/set screw. I hand tightened the barrel, torqued set screws and ordered gauges. The no go gauge is only one that has showed up. The bolt will NOT close on the no go gauge. The bolt WILL close on factory ammo, not as easily as freely cycling bolt, but a little pressure and it drops down and locks up all the way. Cases look fine when I eject them. Any concerns with firing the rifle before the go gauge comes in?

It's quite an expansion on the existing conversation. So for now, I'll just ask the question pending response from OP;

When checking headspace, are you removing the firing pin/striker assembly as well as the ejector from the bolt ?

 

[Rlandry]

There is .010" wiggle room between min/max haedspace as per SAMI spec. All factory ammo is made to fit somewhere in that measurment. A fired case should be conformed to your chamber. You can use the measurement on that case to determine how much shoulder bump you need to use. If you are only going to recreate ammo with factory specs, you won't gain much by reloading. The purpose of rolling your own is to make ammo that is specific to your particular chamber so you can tune for accuracy.

 

[westcoasteast]

It's quite an expansion on the existing conversation. So for now, I'll just ask the question pending response from OP;

When checking headspace, are you removing the firing pin/striker assembly as well as the ejector from the bolt ?

Negative, assuming I should be based on that question? I’m going to take it to a gun smith this next week to be sure, want to learn for my own knowledge, so ask me even the most common sense questions. Assume I know nothing if you haven't already

 

[Threadcutter308]

Negative, assuming I should be based on that question? I’m going to take it to a gun smith this next week to be sure, want to learn for my own knowledge, so ask me even the most common sense questions. Assume I know nothing if you haven't already

Gotcha, Thx. The reason I ask the question is that if the striker is left in the bolt and/or the ejector is also left in the bolt, they will exert pressure on the head (rear/back) of the headspace gauge, making headspace verification more difficult to do so accurately. It makes it particularly difficult if those components are in the bolt and you make a No Go gauge out of a Go gauge and cellophane tape. The ejector will quickly tear up the tape.

It's a double edged sword. For someone that lacks experience with measuring headspace, I would suggest removing the Striker and the ejector. That is because the easiest way to "feel" for proper headspace is if those components are removed. But, that presents it's own set of challenges (removal, not losing ejector/ejector springs, and correctly re-installing them).

Some here will say that headspace can be successfully checked without removing the ejector and striker. While I would agree, I would suggest that the best people to do it that way are people that are very familiar with headspace measurement and they know exactly what they are looking for/what to expect. Any more, the only time I strip the bolt is if I am cutting/chambering a new barrel.

I applaud you taking it to a 'smith. If he would allow it, have him show you what he is doing while he is doing it. Once you see it and have a little explanation to go along with it, it all makes sense in pretty short order.

 

[Yondering]

Factory rounds are usually .002-.004" shorter than a GO gauge. Sounds like it's even tighter than the factory spec ammo.

Hmm. According to your own measurements? My measurements have showed a lot of factory ammo (and unfired new component brass) is often .010"-.015" or more shorter than a go gauge. I've measured as much as .020" shorter in rimless cartridges. Even high quality ammo and brass follows that pattern. For example, the two boxes of Lapua 6.5 Grendel brass I bought recently measure .010" and .018" shorter than the go gauge.

I get the impression that most people think headspace with factory ammo is a lot tighter than it really is, without ever measuring it.

I agree the OP should just shoot it and do some careful measuring of the fired brass, but depending on the ammo I think it's possible he may encounter some that doesn't fit (i.e. maybe the stuff that barely chambers is .015" short, and then he finds another batch that's only .010" short and won't fit). Or maybe it's fine, none of us really know.

 

[Steel head]

OP
Measure base to datum on your GO gauge, new loads and fired loads.

I use barrel nut prefits and I always measure my Go gauge to my new brass.

My 7 saum gauge is 1 thou longer than my new ADG brass so it works out perfect to set it fairly tight to the go gauge and get very little case growth.

 

[westcoasteast]

Shot this weekend, no issues other than some feeding issues mag related. Go gauge came in today and bolt easily closes on it, guess the factory ammo is just tight. Gonna measure go and spent brass later this evening

 

[Holliday]

Ditto...
You could save yourself some coin next time, and just order the go gage.
We're usually not concerned with how close the rifle is to being unsafe to shoot (which is what the no-go does).
Confirm first with the go gage, then add/trim a piece of cellophane packing tape to the back. Adds about .003, bolt handle shouldn't fall.

That’s what I do. Only difference is I use scotch tape which is about .002” on my bolt guns. I do an ever so slight drag on the bare go-gauge.

 

[whatsupdoc]

Shot this weekend, no issues other than some feeding issues mag related. Go gauge came in today and bolt easily closes on it, guess the factory ammo is just tight. Gonna measure go and spent brass later this evening

Take the primer out before you measure, it can protrude and skew your measurements.