Hey all, I have a custom build I put together, first timer.
I got a prefit 300 blackout barrel from Bugholes for the Zermatt Origin action.
I got both a .223 and .308 bolt face. I have the .223 bolt face installed.
I installed the barrel with recoil lug onto the action and torqued to 80 ft pounds, which I believe is within both Origin’s and Bughole’s specs. Used a viper barrel vise and an action wrench with torque wrench to install.
Got the barrel on and installed into the mdt chassis, and took out the firing pin. Put the go gauge in, and it wouldn’t close.
(1) Many tutorials tell me to take out the ejector and extractor. For the zermatt origin, there doesn’t seem to be an ejector on the bolt, is the ejector in the back of the action? Like a piece that kicks it out when the action is pulled all the way back?
(2) I couldn’t figure out how to take out the extractor, and many said that isn’t necessary and can bend if taken out. Is it critical to remove the extractor?
(3) could the recoil lug be an issue? Both sides looked the same, but I wasn’t sure if one side should be used instead of the other. I couldn’t see a difference there.
Edit: removed the extractor too, still won’t close on go gauge.
Edit: Also, it seems to close fine over a steel dummy 300 blackout round.
Edit: bolt will not close on a factory 220 grain AAC round either
Edit: tried the new 6.5 Creedmoor barrel for it too, and that one closes properly on the go gauge and does not close on go gauge. Issue seems to be with 300 blackout barrel
Is it getting stuck camming over the case head? Origins are controlled round feed, so it would be best to slip the case head under the extractor and not force it to cam over the go gauge.
Do you have the recoil lug installed?
Does it close on the no-go gauge?
I manually load the go gauge under the extractor onto the bolt and then slide it into the chamber. The extractor is not being pushed over it, I make sure the extractor grabs onto it when the bolt is open and then try closing with it on.
Yes, the recoil lug is installed between the barrel and the action. The lug has a pin that fits into the action, it seems nice and properly fit.
I haven’t tried the no-go gauge. If the go gauge doesn’t close, I imaging a no go gauge would be longer and not close right? I’ll give it a try now.
I would try a round of 300 blk with the firing pin removed to see what that does.
Otherwise, sounds like you have a short chamber. It may be worth un torquing the barrel, putting the gauge in the bolt face, and twisting the barrel down until it stops on the gauge, hand tight. You can use a feeler gauge between the barrel shoulder and recoil lug, and tell your barrel maker how short it is. At least, that's how I would approach this.
Confirmed now that no go gauge won’t close either. I removed the extractor too, and go gauge still won’t close.
Are you the original owner of the action? If not, make sure you don't have the .150" lug on it that makes it compatible with TL3 barrels
Pretty sure the little card that came with my Origin said to remove the extractor when checking headspace. It's not difficult, you push the detent in the middle of it into the bolt and slowly slide the extractor off. Be careful not to launch the detent and spring while doing so.
Gotcha, I got the extractor and firing pin removed, and the bolt still won’t close on the go gauge.
Sounds like the barrel needs to go back to the manufacturer. I definitely wouldn't shoot it.
This is assuming it is a shouldered prefit. A barrel nut setup you have to manually set headspace.
Yes it’s a prefit. I couldn’t shoot it if I wanted to, it doesn’t close on a factory round.
Do you have any sized cases you could try
Not presently, what is that? Like unfired brass?
Fired, unfired. Just sized to the correct dimension.
What caliber go and no-go gauges are you using (have to ask)?
It is a Forster 300 blackout go gauge that I am using. This one:
https://preview.redd.it/tbzwqb3pzv9g1.jpeg?width=4032&format=pjpg&auto=webp&s=79b6340234c8aea98728104aaa1eb7cd2dee24fd
https://preview.redd.it/bgd5qnx10w9g1.jpeg?width=4032&format=pjpg&auto=webp&s=e3ee1428ea9dda99487aca50b0c7256af82a0800
If you are renting the gauges, sometimes people put scotch tape on the backs as a way to make their own “no go”guage. Check that is t happening to you accidentally.
Thanks, I bought this gauge new and it was sealed.
Can you dimensionally measure the go gauge and compare dimensionally the no-go gauge? I wonder if the go gauge is wrong (wrong etch calling it a go gauge when it is a no go gauge).
This, given that you added (edit) that it closes on a steel dummy round. Trust…but verify.
link to SAAMI spec website to published pdf
Go to page 102 for 300BO. The Circle X (X-MEN symbol) notates the headspace gauge reference. Not sure if to can measure this though.
Do you have calipers? Check to make sure the gauge is in spec before blaming the barrel.
You can't make sure a headspace gage is in spec with calipers.
I have two Zermatt’s (Ti3 and TL3) with Bughole barrels. I’ve had nothing but excellent results with them.
There was some conversation at the range that Southern Precision Rifles had been sold in the past couple years and quality had gone down. That’s not my experience, but that’s what others (who are gossipy but more plugged in to the scene than I am) said.
Just contact them and ask for help. Every time I thought there was an issue it was my problem/mistake at fault. Just tell them you are having some headspace issues and need some guidance.
Yea I plan on doing that too when they open on Monday.
Couple things, you should measure and double check the dimensions of the gauge and see how it compares to the no-go. You may need a headspace compare tool.
You said you loaded a fired piece of brass and it closed but that is not the best tool. If you don't reload, you should try a piece of factory ammo and see if it closes with no resistance. Then you will know the headspace is not super short.
If you do reload, or know someone who can get you a full length resized case, you can try some of that brass and see what happens.
I haven’t tried a piece of fired brass, don’t have any around. Will try factory ammo.
If it closes fine on factory ammo, I’m guessing that doesn’t mean it’s safe unless the go gauge is out of spec.
If it closes on factory ammo but not the no-go gauge, it means the go gauge is fucked. Because there's probably only 3-7 thousandths of difference between the bolt closing on a fired round and not closing on the no-go gauge. That also means you are probably g2g if the stripped bolt closes on a live round with no (and I mean absolutely zero) resistance. If there is any resistance at all, it means the shoulder is rubbing on the chamber shoulder and the tolerance is too tight. Factory ammo headspace is very generous because they need to fit in any and all chambers with all sorts of headspace so if factory ammo is a snug fit, the headspace is too short to feel comfortable. The only way you know the gun is G2G is if a live round chambers with a fully stripped bolt with no resistance whatsoever. The bolt should fall on its own like there is nothing In the chamber.
Tried some factory AAC 220 grain sub and the bolt would not close.
Aaaaaand now it's time for an email or phone call to Bugholes for a conversation. Headspace is way too short and the go gauge is probably correct. If the bolt won't close on factory ammo, she fucked.
Thank you. I ordered two barrels from him, one is a 6.5 Creedmoor. I will try installing that with the .308 bolt and check headspace, I have some 6.5 cm headspace gauges too.
Yea do that for sure
Just checked and the 6.5 Creedmoor go gauge closes properly, and the no go gauge does not close.
Must just be an issue with the 300 blackout prefit. I’ve tried multiple times and adjusted torque tried with and without extractor.
Yup and it also indicates that your action is NOT fucked. It's definitely the barrel
You chose a good guy to get a barrel from though, bugholes has a good reputation and should make it right.
The only reason a live round chambering with no resistance would be bad is if the no-go gauge also was able to be chambered with bolt closed. That means there is TOO much headspace and a factory round could possible not be full pushed forward during the firing operation and would not fully contact the shoulders of the chamber and allow pressure to escape around the shoulders.
But since we know the no-go gauge does not allow bolt close, we know the chamber headsoace is not too much. The only worry at this point is short headspace
So on my tl3 actions the extractor won't cam over my gages. To get around this I turn the barreled action upside down and slide the gage under my extractor just like a round comming out of the magazine.
Yes, that’s what I did, I slid the gauge under the extractor. Then I removed the extractor. Won’t close on go gauge either way
One other idea. Are you the first owner of this action? Do you have the original factory lug? I know they make lugs to adapt the origin to take a tl3 barrel.
I am the original owner. Do you mean recoil lug? Yes, I only have the factory recoil lug that came with it.
Ok thats not the issue then. I think its time you called the guys who made the barrel.
Please reply back here on what you found out
My 300 blackout prefit barrel doesn’t let the action close on a go gauge or a factory live ammo. Removed firing pin and extractor too.
My 6.5 prefit barrel does close on the go guage and not on the no go gauge, so that’s good. Means the action is good and the issue must be with the 300 blackout barrel.
I emailed bugholes and they asked if I have some unfired brass to try on, which I don’t have. But since it doesn’t close on a factory live round, not sure what good closing on unfired brass would do since I wouldn’t be able to fire it.
I think I’ll need to send the barrel back.
Side note, when I put the .223 stripped bolt face on the 300 blackout barrel, it will not close on the go gauge. But when I put the .308 strippped bolt face on the 300 blackout barrel, it will close with the go gauge. Perhaps the issue is the .223 bolt face