Go gauge for shouldered prefit?

FireFlyFishing said:

Let's say I didn't have the means to put together a prefit, so I took it to a smith to ensure the job was done properly. I interview the smith if they use gauges. If the smith wouldn't tell me or they said "no, I use a case and scotch tape," I'd be taking my rifle elsewhere. What would you do?

This is another reason I'm loath to buy "custom" rifles off the classifieds. I have no idea how the rifle was built.

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I think any gunsmiths you take it to is going to say yea, I use gages or we set the headspace between min and max….good day. Are you asking Remington or Tikka to prove the use gages? Maybe they don't?? Maybe they make their own….I'm actually sure they do!

Next are you going to ask for video on how they mix their epoxy?

I'm being silly, obviously, but it is to make a point that customers choose a gun builder, not how they build the guns.

nksmfamjp said:

I'm being silly, obviously, but it is to make a point that customers choose a gun builder, not how they build the guns.

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I would argue you choose the gun builder/smith because of the way he/she builds a gun. A good reputation usually favors the good smiths…for obvious reasons.

I say do what you like. The OP asked and I gave my response. After reading this thread I'm even more apprehensive to buy a "custom" or "semi-custom" rife from the classifieds.

Some of you need to look at what SAMMI specs and the tollerances are for each component, your getting way to wound up!!
A go gauge and scotch tape or a shim tells you more than a no go that's why so many do it that way, I like the .001 shim because I used to just have them on my lathe and didn't have to mess with tape.

A no go is between .004 and .006 over go but STILL .004 -.006 UNDER max spec per SAMMI.
Ideally your headspace is set to match your dies, use your go gauge and tape and check your dies, you might find drag on a go gauge is just right, you might find .004 is just right. The tolerance stack, by the time you go from vigin brass to max allowable chamber is much larger than a thou here or there.

Really you just need a basic check of what range your in, with prefits make sure you give it a couple thou breathing room so your down stream process doesn't suck.

MagnumManiac said:

Are these AR barrels a pre-fit to a PARTICULAR rifle, or are they a GENERAL barrel for AR's.
This is TOTALLY DIFFERENT to a pre-fit for ONE ACTION…

I've been gunsmithing a long time, pre-fits don't exist here, but I can machine numerous barrels, chamber them and fit them to ONE ACTION, MY OWN.

You are all confusing what a pre-fit is.

Cheers.

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That's my whole point. Barrels that are supposed to be "MIL-Spec" are not always mil spec. You will never see a military armorer install an M-16/M4 barrel with out checking headspace and it's my policy to check headspace on every rifle that comes into my shop.
I do not use pre-fit barrels on custom rifles of any variety. Pre fits, especially shouldered pre fits absolutely need o have headspace checked. At least with a Savage type barrel, end users can set headspace during the install but, of course, need headspace gauges to do that.

Taj said:

That's my whole point. Barrels that are supposed to be "MIL-Spec" are not always mil spec

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This thread has nothing to do with 'Mil-spec'. This is YOUR take on the meaning of a shouldered pre-fit, it is definitely not mine…

Cheers.

Everyone makes mistakes. The best smiths out there have made mistakes and lots of trusted vendors have been called out for mistakes.

So, I take the extra few minutes to confirm. In the grand scheme of things when it comes to cost and time that I invest in this sport, it doesn't even register as a blip.

On Shouldered Pre Fits, can someone direct me to a vendor that sells the premium pre fits (Bartlein, Brux, Kreiger) cheaper than what the average cost is from a gunsmith?

V35BTC said:

On Shouldered Pre Fits, can someone direct me to a vendor that sells the premium pre fits (Bartlein, Brux, Kreiger) cheaper than what the average cost is from a gunsmith?

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What action?

MagnumManiac said:

This thread has nothing to do with 'Mil-spec'. This is YOUR take on the meaning of a shouldered pre-fit, it is definitely not mine…

Cheers.

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I think you are wasting your breath. There are lot of things off with that whole response.

pavementends said:

For educational purposes only, If your go gauge lists a length on the side as mine do, measure it with your calipers and comparator. This allows at least an indication of the comparator and caliper. Also may show why numbers from my comparator may not agree with yours. They are quite useful to compare the difference between your go gauge and no go gauge or taped go gauge. At some point we have to decide who we trust. I do prefer to have a at least a go gauge.

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Exactly. You can use a Hornady headspace comparator, make an absolute measurement of the go gauge and the difference between your calipers' measurement and the label on the go gauge is the chamfer of the comparator. Mine is 0.008". So, when I add 0.008" to any measurements with that comparator, I know the exact headspace length of brass vs SAAMI spec. Of course, headspace gauges and Short Action Customs have tapers in them and one hopes they all agree with relative measurements. When they don't, you may want to reference back to that non tapered Hornady datum-only method

Hydra6 said:

What action?

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TL3, Origin, AntiX, Kratos

V35BTC said:

On Shouldered Pre Fits, can someone direct me to a vendor that sells the premium pre fits (Bartlein, Brux, Kreiger) cheaper than what the average cost is from a gunsmith?

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It's not all about cost. It's about convenience. No need to send your action to a smith and wait. You can order a barrel when you know yours will be going out in a few months and keep shooting it out and then the other barrel is there to swap over to and keep shooting.

But you send any barrel to any smith that does prefits and they can do it for you even if they don't stock that barrel brand.

MagnumManiac said:

This thread has nothing to do with 'Mil-spec'. This is YOUR take on the meaning of a shouldered pre-fit, it is definitely not mine…

Cheers.

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Brother, I'm not here to argue with you and I think you are misunderstanding my point. All I'm trying to say is that manufacturers make mistakes and that headspace should always be checked on a prefit barrel install. I'm not exactly new at this. I've been a gunsmith in my own, very active shop for right at 50 years and have barreled hundreds of guns and have seen a lot of mistakes by probably every manufacturer. Nobody is perfect. There is always a question mark with prefits and tolerance stack-ups between barrel and action manufacturers can add up and may not give you optimum results, which is why I never personally used them in my shop. I'm sure there are good ones out there but I put a lot of effort in setting up a barrel for chambering and prefer to do it that way if my name is attached to it.