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why did ARC suspend Barloc sales?
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I banged my barrels around today, proof cf 6.5 saum in a l/a nuke and brux #4 contour 6.5 creedmoor in a s/a mausingfield, both with barlocs. 5 rounds as a baseline, bang a direction 3 times as hard as I care too with my palm, 5 more rounds.
I made a bunch of .5-.8" 10-shot groups.
Thread fit is tight on both barrels. I have a looser prefit from PVA but I'm waiting to get some QC issues worked out with it before I shoot it anymore.
I made a bunch of .5-.8" 10-shot groups.
Thread fit is tight on both barrels. I have a looser prefit from PVA but I'm waiting to get some QC issues worked out with it before I shoot it anymore.
No, that's what I was implying. I shot 5, banged the barrel, shot 5 more and they all landed in 1, 10-shot group less than 3/4".
I tested this to a degree with two PVA barloc prefits, a pacnor and a proof Savage prefit. No issues with the Savage pre-fits and one of the PVA barrels however the one for my Win Mag had an issue at first. When I initially put it on I must have had some build up on the gauge and it was not screwed in far enough. If I smacked the barrel there was a visible movement and the POI would shift by feet. So I tightened the barrel down another .002, everything locked up tight and started producing 1 hole groups with no issues chambering my handloads or factory ammo. Repeated smacking at this point yielded no more movements.
This I believe could be the root cause of the issues, if the shoulder is cut slightly to far forward, the barrel is not screwed in far enough to match the shoulder or the barrel nut is not tight enough then there isn’t enough force transmitted to the barrel to lock it in place which results in the shifting. So long story short it appears that as long as they are properly installed there shouldn’t be any issues with the barrel shifting.
This I believe could be the root cause of the issues, if the shoulder is cut slightly to far forward, the barrel is not screwed in far enough to match the shoulder or the barrel nut is not tight enough then there isn’t enough force transmitted to the barrel to lock it in place which results in the shifting. So long story short it appears that as long as they are properly installed there shouldn’t be any issues with the barrel shifting.
Sounds like the the two "flanges" of the Barloc which the clamping bolt runs through are not properly spaced either due to improper barrel shoulder or headspacing. I suspected this when I saw examples where once tightened down there was no gap prior to getting torqued down. This makes sense now.
With the PVA prefit that I have (shouldered, barloc), I completely close the barloc top gap installing the barrel so I could see how it wouldn't be as "tight". I think this is because they're hitting the shallow side of chamber depth. Judging by a couple of barrels I've spun up myself they could stand to go about .005-.007" deeper in my particular case. I also noticed a lot more POI shift from one install to the next with a Savage prefit barrel I had (jam nut style) previously, so I can see how both of those situations could cause the POI shift issue.
I'm waiting on PVA for return shipping label to handle some QC issues with the prefit, but once I get it fixed or replaced I'll see how the fit is and if it shifts with impact.
I'm waiting on PVA for return shipping label to handle some QC issues with the prefit, but once I get it fixed or replaced I'll see how the fit is and if it shifts with impact.
Ledzep - Are you installing the Barloc correctly when using a Savage/Jam Nut? ARC says that once you set headspace the nut should be tightened to the point it spreads the split collar about the width of the ARC barrel nut wrench thickness then torque the cross bolt down. For the Barloc Shoulder Prefits I can see adding a few peel washers or shims to the barrel shoulder could provide the necessary "loading" prior to tightening down the cross bolt.
The potential for POI shift when swapping out the same barrel because you may not be setting it up consistently but once the barrel/Barloc is installed correctly there should be any POI shift.
The potential for POI shift when swapping out the same barrel because you may not be setting it up consistently but once the barrel/Barloc is installed correctly there should be any POI shift.
I'm sure if you install it to their instructions you'd be better off. How much so I have no experience. I made my own nut from a Savage nut I had, before you could readily get ARC nuts. I did not torque the nut more than hand tight before tightening the barloc screw. I never had POI wander issues with the barrel installed, but could clock POI shift based on where the barrel nut was clocked, and if I didn't pay attention to it, I had about 4x the variability in POI shift from removing/reinstalling the barrel that I have with my shouldered setups.
My Savage style barrel is shot out and long gone now, so I doubt I'll mess with the savage prefit style barrels again unless I lose access to lathes (not likely).
My Savage style barrel is shot out and long gone now, so I doubt I'll mess with the savage prefit style barrels again unless I lose access to lathes (not likely).
I emailed Arc here’s the response I got
We have not had time to test it thoroughly yet, but we believe it is possible. We advise people to not use it for competition shooting or hunting. If you are going to use it we recommend that you test it out yourself. You can try to add anti-seize around the conical surfaces to try and distribute the friction. We believe that it is caused because there is more friction at the top of the barloc by the bolt than at the bottom, so when the barrel is struck on or by something it shifts the barrel to settle in to the conical surfaces of the barloc. But again we have not had time to test it.
We have not had time to test it thoroughly yet, but we believe it is possible. We advise people to not use it for competition shooting or hunting. If you are going to use it we recommend that you test it out yourself. You can try to add anti-seize around the conical surfaces to try and distribute the friction. We believe that it is caused because there is more friction at the top of the barloc by the bolt than at the bottom, so when the barrel is struck on or by something it shifts the barrel to settle in to the conical surfaces of the barloc. But again we have not had time to test it.
I ordered the barrel nut, split collar, and recoil lug all separately. Cost me an additional $15 over buying it as a set but at least I've got parts coming in for my build. I'm confident if installed correctly there should be no issue.
They will be releasing version 2.0, the Kratos. Get your preorder in January!
I tried my PVA Prefit .308 barrel for POI shift tonight and got quite a bit. About a mil from center.
Previously I tested my 6.5 SAUM, 6.5 Creedmoor, and .300 PRC barrels for the "smack test" and none have shown any notable POI shift.
I believe the difference is this: All barrels have a 1.275" long tennon (even the .308). My 6.5's and 300 PRC barrels have .145" of GO gauge exposure off the breech face. The PVA Prefit has .153" exposure. In other words, the head space is about .008" shallower, so the barrel isn't screwed in as far-- it's completely loose away from the barloc to headspace, and the barloc has to expand before locking it in place.
I'm going to hand ream the .308 barrel to get .145" exposure and try again.
Previously I tested my 6.5 SAUM, 6.5 Creedmoor, and .300 PRC barrels for the "smack test" and none have shown any notable POI shift.
I believe the difference is this: All barrels have a 1.275" long tennon (even the .308). My 6.5's and 300 PRC barrels have .145" of GO gauge exposure off the breech face. The PVA Prefit has .153" exposure. In other words, the head space is about .008" shallower, so the barrel isn't screwed in as far-- it's completely loose away from the barloc to headspace, and the barloc has to expand before locking it in place.
I'm going to hand ream the .308 barrel to get .145" exposure and try again.
Stayed put as far as I could tell.
And yes, shimming the barrel would do the same thing as reaming the chamber deeper. Reaming it in my case is easy enough, and keeps 1 less item in the chain.
Just thought-it would be super easy to make a barloc with the nut work like the bugnut setup with a larger shank barrel.
A Allen wrench is far cheaper than the bugnut wrench and easier to do in the chassis/stock and without removing the scope.
A Allen wrench is far cheaper than the bugnut wrench and easier to do in the chassis/stock and without removing the scope.
I watched multiple videos about this system and i can hear myself saying...."ILL STICK TO SHOULDER BARREL" over and over
Yeah, that's true too. The thread fit on the PVA is also looser than my other barrels. The others I did myself (well, one is Area 419) and are very close thread fit. Could be another reason why. I'll cut the HS shorter tomorrow and see if that fixes it.
What do you mean by 5-6 under bighorn TL3 spec? Specifically which dimension are you referring to?
We run Class 3 thread fits on all the barrels. They are checked with ring gages for GO/NOGO before they leave the lathe on every single barrel. Some oddballs like M26x1.5 (Howa actions) get measured with PD mics instead but they are still 100% checked prior to removing from the lathe spindle.
Class 3 has a 3.8 thousandths wide band on the male thread (PD 1.0300/1.0262)
To my knowledge, and I've sent a text over to a friend at Bighorn to confirm this morning, they are running a Class 3B (Class 3 Internal) thread on the receiver tenons and this has not changed in years.
The whole thread spec is:
| Diameters | |
|---|---|
| Definition: | (1.0625)-20 UNC 3A (External) |
| Major diameter: | 1.0625 / 1.0544 |
| Pitch diameter: | 1.0300 / 1.0262 |
| Minor diameter: | 1.0030 / 0.9894 |
| Over wires: | 1.0827 / 1.0789 |
The major diameter has the most allowance because there is no thread load there. We run threads at 1.057-1.058 on the major to protect thread crests and make the fit more reliable.
The female thread has similar allowances for clearance
| Diameters | |
|---|---|
| Definition: | (1.0625)-20 UNC 3B (Internal) |
| Major diameter: | 1.0747 / 1.0625 |
| Pitch diameter: | 1.0350 / 1.0300 |
| Minor diameter: | 1.0161 / 1.0084 |
| Over wires: |
There are a lot of reasons why threading to minimum clearance is a bad idea. We are not a "thread to fit" shop and never have been. That's a recipe for stuff that galls, doesn't fit, or gets damaged during installation. We aim to work towards the bottom 25% of the spec for male threads and the top 25% of the spec for female threads so that things always fit and there is a far reduced risk of parts galling or getting stuck when improper lubrication or dirt is in the joint.
If someone were to make a "thread to fit" barrel for a max 3B receiver it would be somewhere in the PD 1.034-1.035 range, 4+ thousandths oversize on the allowed spec and something that would not fit a receiver that fits a plug gage at the other end of the allowed spec.
If I can remember this afternoon I'll grab some thread wires and mic my barrels for comparison. My previous statement was just based on feel.
My action is a MF, not a TL3.
My HS comment is based on tennon length and GO gauge exposure out of the breech (uninstalled barrel). All 4 are 1.275" tennon, but the 308 is .007-.008" more go gauge exposure. Means I don't have to screw it into the receiver as far for head space, and there's a small gap between the shoulder and loose barloc at headspace. Tightening the barloc closes the gap but the barloc bottoms out, too.
So by cutting the chamber a scoshe deeper, may be able to nail down the cause of the POI shift reports... Hopefully.
My action is a MF, not a TL3.
My HS comment is based on tennon length and GO gauge exposure out of the breech (uninstalled barrel). All 4 are 1.275" tennon, but the 308 is .007-.008" more go gauge exposure. Means I don't have to screw it into the receiver as far for head space, and there's a small gap between the shoulder and loose barloc at headspace. Tightening the barloc closes the gap but the barloc bottoms out, too.
So by cutting the chamber a scoshe deeper, may be able to nail down the cause of the POI shift reports... Hopefully.
I don't know where others mentioned thread their barrels to it now, I've seen statements in the past by one of the people you mentioned that he uses receivers as the GO gage (aka thread to fit). If you're measuring on wires the numbers I quoted above are for .0320 wires.
We haven't had anyone that I can remember telling us that our barrels had a POI shift but that could be just my memory failing as well, it's been busy lately. The one that I do know had issues with his had barrels that were threaded to fit very tightly to a Nucleus. There have been folks from a lot of different fitting shops saying they had the same problem. Didn't seem to matter how it was done, tight or loose. It would be nice to see the BarLoc problem(s) solved as it's a pretty handy little trinket but at this point I'm hearing mixed info from enough different places that have tried tight/loose/long HS/ short HS/ etc that we just can't advise it right now.
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This is correct, we check every action with a 3B thread gauge when we perform that operation. - Ray
The Barloc issues you've heard of, are they on shouldered barrels or barrel nut styles too?
Thanks, Ray, I appreciate the confirmation.
So far, everything I've heard has been on shouldered stuff.
1. The nut-style barloc instructions say to expand the barloc device until you can fit a wrench inside the gap-- so before you even start tightening the barloc screw there is pretension on the threads. There's no chance of bottoming out the barloc screw clamp.
2. The nut on the savage style setup is directly connected to A) a conical interface with the barloc, and B) threads on the barrel. With the shouldered setup there is a flat plane where the shoulder meets the front ring of the barloc.
Hopefully in a few hours here I'll be able to see if tension on the barloc (enough pre-load to prevent the gap from closing all the way) will fix the POI shift issue.
2. The nut on the savage style setup is directly connected to A) a conical interface with the barloc, and B) threads on the barrel. With the shouldered setup there is a flat plane where the shoulder meets the front ring of the barloc.
Hopefully in a few hours here I'll be able to see if tension on the barloc (enough pre-load to prevent the gap from closing all the way) will fix the POI shift issue.
I don't know if this will help at all as I haven't tested my Barloc to extremes, but during installation, I would torque, gently tap around barloc/ end of the barrel, torque and repeat until it settled and wouldn't back down from the 90 in/lbs of torque. I do the same at work, but with more enthusiasm and with a hammer and punch. Also lubed the contacting faces with a small amount of anti-sieze.
I just smacked my barrel hard with this.
No changes in POI.
No changes in POI.
Got the .308 barrel chamber cut a little deeper so it matches my others. 1.275" tennon, .145" GO gauge exposure. YMMV but this setup in my Nucleus and Mausingfield headspaces exactly as the shoulder touches a loose Barloc...
Shift problems appear to be gone. I shot 40 rounds and didn't see any evidence of POI shift.
5 shots for a reference group
Hit the left side
5 shots
right side
5 shots
top
5 shots
bottom
5 shots
one big hole.
The rest of them I shot 5-round groups where I'd perform the above, just with 1 shot per direction to make 5-round groups. This was factory hunting ammo, but all of the 5-shot groups came out .5-.8" or so. The 25-shot first group was a big hole a little over 1.1 MOA. I'm sure I didn't hold perfect on every shot, either. At any rate, the 1+ mil shifts are not happening at all. I may repeat this with handloads at some point to get a little more precision in the test... Or I may not.
Good enough is good enough sometimes.
So it would appear that clamping power is the solution. I didn't hit the barrel as hard as I absolutely could, but simulated what I'd expect moving between holes on a barricade wall.
Shift problems appear to be gone. I shot 40 rounds and didn't see any evidence of POI shift.
5 shots for a reference group
Hit the left side
5 shots
right side
5 shots
top
5 shots
bottom
5 shots
one big hole.
The rest of them I shot 5-round groups where I'd perform the above, just with 1 shot per direction to make 5-round groups. This was factory hunting ammo, but all of the 5-shot groups came out .5-.8" or so. The 25-shot first group was a big hole a little over 1.1 MOA. I'm sure I didn't hold perfect on every shot, either. At any rate, the 1+ mil shifts are not happening at all. I may repeat this with handloads at some point to get a little more precision in the test... Or I may not.
Good enough is good enough sometimes.So it would appear that clamping power is the solution. I didn't hit the barrel as hard as I absolutely could, but simulated what I'd expect moving between holes on a barricade wall.
Got the .308 barrel chamber cut a little deeper so it matches my others. 1.275" tennon, .145" GO gauge exposure. YMMV but this setup in my Nucleus and Mausingfield headspaces exactly as the shoulder touches a loose Barloc...
Shift problems appear to be gone. I shot 40 rounds and didn't see any evidence of POI shift.
5 shots for a reference group
Hit the left side
5 shots
right side
5 shots
top
5 shots
bottom
5 shots
one big hole.
The rest of them I shot 5-round groups where I'd perform the above, just with 1 shot per direction to make 5-round groups. This was factory hunting ammo, but all of the 5-shot groups came out .5-.8" or so. The 25-shot first group was a big hole a little over 1.1 MOA. I'm sure I didn't hold perfect on every shot, either. At any rate, the 1+ mil shifts are not happening at all. I may repeat this with handloads at some point to get a little more precision in the test... Or I may not.
So it would appear that clamping power is the solution. I didn't hit the barrel as hard as I absolutely could, but simulated what I'd expect moving between holes on a barricade wall.
Thanks for the tenon and exposure numbers.
I’m planning on another barrel soon and that helps.
I noticed when I was preloading the nut to the point where the clamp spread enough to get the wrench in the cut it was a good bit of resistance to the little spanner wrench.
Thanks for clarifying. It is exactly where it's supposed to be on the gaged/mic'd class 3 fits then.
For what its worth, we are running 4 bar locs "barrel nut" style on nucleus actions and they have been flawless, we preloaded and torqued per teds recomendations and everything has been great, we have beat them and shot hard in PRS comps and no POI shift or anything.
I think most of the mentioned Barloc issue is with shouldered barrel install, not the barrel nut.
I'm currently running a shoulder barrel Barloc, but the rifle is new, so i haven't ran in to POI shifts or banged the barrel to checl POI shift.
I'm currently running a shoulder barrel Barloc, but the rifle is new, so i haven't ran in to POI shifts or banged the barrel to checl POI shift.
I believe they were putting all their effort into the new actions so the barloc was on hold for the foreseeable future. That being said check Mile High as they have some in stock.
Sounds like most of the issues stemmed from shouldered prefits that bottomed out on the headspace gauges before they had enough torque down on the collar to spread it open. I have a non-shouldered prefit and took two deer this year without issue. Reconfirmed my zero a couple times through the season after beat it through the bush and also kicking my rifle barrel accidentally while walking around in the dark. Sample size of one but I myself have no concerns.
The above scenario was the problem situation.
My barrel nut version Has been GTG.
My barrel nut version Has been GTG.
Yep - I've got two, one on a Mausingfield and one on a Bighorn. I haven't swapped barrels on the Mausingfield, but I've swapped barrels on the TL3 dozens of times. I have to rezero when I put the new barrel on (it's close, but not centered) then after that, I can use my come-ups from the last time I had that barrel spun on.
I checked last night and they have some Barloc's in stock presently.
My testing mirrors the above. If the chamber was cut shallow enough that the Barloc completely closed the gap on top when tight, the barrel could be shifted around. If there's still a gap after you torque the clamp screw, you're set.
I've spun up 4 barrels now myself, and corrected 1 prefit to the same numbers for tennon length and GO gauge exposure and haven't experienced any POI shift over a season of practice and PRS/NRL style local matches.
I've spun up 4 barrels now myself, and corrected 1 prefit to the same numbers for tennon length and GO gauge exposure and haven't experienced any POI shift over a season of practice and PRS/NRL style local matches.
If you don't have a Borka torque limiter, the one below (10 Nm) seems to work well, and something you can just toss in your bag:
ETA: To torque the Barloc bolt.
ETA: To torque the Barloc bolt.
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