8.6 Blackout headspace

[Chillertech]

Anyone have a 8.6 blackout set of headspace gauges they could measure for me, I ordered a set of PTG headspace gauges and they both measure 1.4045.

 

[4O6shootist]

Parent case is the creed, should be the same I'd think? Problem is, you're comperator that you're using to measure headspace on your gauge, isn't going to be an exact dimensional copy of someone else comperator used to measure a gauge. You'll see different numbers.

 

[Chillertech]

I should have posted more info, I have a Faxon Remage 16” barrel I’m trying to set the headspace on, I just started out with the go guage and adding layers of tape, got to 3 layers of electrical tape and the bolt will still close with no resistance(firing pin and ejector removed), so i ordered the no go just to see if that made any difference, I’m starting to wondered if the barrel is chambered correctly.

 

[Supersubes]

Parent case is the creed, should be the same I'd think? Problem is, you're comperator that you're using to measure headspace on your gauge, isn't going to be an exact dimensional copy of someone else comperator used to measure a gauge. You'll see different numbers.

The 8.6 and creed are quite different.

 

[4O6shootist]

The 8.6 and creed are quite different. View attachment 8239179

It most definitely is! I knew it used the creed parent, but didn't realize they moved the shoulder that far back. Clearly a cm gauge will not do anything for the OP, I put my foot in mouth there.

I should have posted more info, I have a Faxon Remage 16” barrel I’m trying to set the headspace on, I just started out with the go guage and adding layers of tape, got to 3 layers of electrical tape and the bolt will still close with no resistance(firing pin and ejector removed), so i ordered the no go just to see if that made any difference, I’m starting to wondered if the barrel is chambered correctly.

Since it's remage, I'd take your go gauge, add one or two layers(max) scotch tape, and spin the barrel on till contact is made with the gauge, and tighten the barrel nut down. This will leave you with a headspace of go gauge plus 002-004 depending on how tight you spun barrel up against gauge. Most smith's who cut custom chambers cut to go plus 002. Black electrical tape has to be thicker than scotch and at 3 layers, that's prob go plus 009 at least. Sounds like headspace is off. Simple test, put scotch and black in your caliper and check thickness.

 

[db2000]

Mos-Tek actually requires you to send your bolt in so they can assure proper headspace. They seem like a good company with fairly timely email responses. You could maybe reach out to them for advice. That being said I just read the above advice and that seems reasonable also.

 

[Chillertech]

I did start out with just the go guage and tightened just until contact was made and backed off very slightly so the bolt would open, tightened barrel nut down not to the final torque value but hand tight, took the go guage and started with layers of Scotch tape first, got to three and and still no resistance on bolt close, that’s when i started with the electrical tape, I will do it again and measure with calipers and see what that tells me, I just wish I would have went the Mos-Tec route but I was being cheap when I found a deal on the Faxon barrel.

 

[msgriff]

Are you measuring the OAL of the gauge?

 

[Chillertech]

Yes

 

[Supersubes]

Yes

So you didn't use a comparator?

 

[Chillertech]

No, I don’t have a comparator.

 

[msgriff]

Headspace is measured base to datum. The datum on a (*) bottle neck cartridge/chamber is typically on the shoulder. The datum of the 8.6 BO is at the point on the shoulder where the diameter is 0.400". OAL of your gauge means nothing. Here's a print:
ETA: (*) = non-belted

 

[Chillertech]

Ok, I see, looks like I need a comparator to accurately measure my go no go gauges, thank you for that info.

 

[Supersubes]

Ok, I see, looks like I need a comparator to accurately measure my go no go gauges, thank you for that info.

Yes you need a comparator because its a good tool, but for now just go reset headspace on the go gauge, then try the no-go.

 

[Chillertech]

Just tried it again, same thing, put in the go gauge, tightened until contact, loosened slightly so that the bolt moves freely, tightened the barrel nut hand tight bolt still moves freely, put no go gauge in and there is no resistance at all.

 

[ZY100]

Your doing it wrong. Dont tighten and then back off.

- put two layers of scotch tape on the base end of the go gauge
-tighten the barrel until snug contact
-tighten barrel nut hand tight
-remove go-gauge
-tighten barrel nut, don’t t let barrel turn
- remove scotch tape and ensure bolt closes on go gauge
-put three layers of tape on base of gauge and bolt should not close

If the last two steps don't work, start over.

 

[4O6shootist]

Yes

Perhaps try this, apply one layer scotch to the go gauge. Spin barrel to contact. Tighten barrel nut. Remove the go. Test no go, if no close, good. Then test go, it should drop the handle closed. This is with firing assembly and ejector removed from bolt body.

 

[Chillertech]

I will try this, the only reason i was backing off was if i tightened until contact with the go guage the bolt wont open without some force applied.

 

[Chillertech]

Also the firing pin assembly and ejector are removed.

 

[ZY100]

Is this a new action? Be sure you have some lube on the bolt lugs.

You could use a sharpie to make a witness mark, back it off, remove the gauge, then reset to the witness mark and tighten.

 

[Chillertech]

Yes, it is a new Kauger Arms action, the back of the bolt lugs are lubed, I’m going to try all these suggestions in a few, thanks for all the help guys, I will report back!

 

[Chillertech]

Ok, so i followed ZY100’s advice and i had to add about 5 layers of Scotch tape to get resistance on bolt close.I measured the tape layers at .0185.

 

[ZY100]

Close but still too far you want .002-.004 added to your go to not close or just barely start. Use your witnessed mark, screw the barrel in about 90 degrees. Then check go and go plus 2 or 3 layers of tape.

16 TPI is 0.063 per rotation. Quick math…I think about 90 should do it.

PS…thats some thick scotch. Usually about 0.0015 or so.

 

[Chillertech]

I finally got it, it was very touchy, more so than i remember doing before, though its been a few years since I installed a Remage barrrel, had to add 3 layers of tape measured at .004 before i got resistance on bolt closure! Thought it was gonna whoop my azz!

 

[ZY100]

Glad it worked out!