Barrel Nut Disadvantages?

[DShortt]

I think it is fair to note that it's been said a difference of .1" would be considered huge. That matters to shooters here who compete in the arena of precision but not so much to those who complete in the arena of accuracy or just like to shoot a smaller group than their buddies.

 

[jackieschmidt]

Well, I decided last night to go on ahead and take the barrel off of my 17 pound Rifle and modify it for the nut.
This is a 1-17 Bartlien 30 cal that is a proven winner. I decided against going to the range with it, then coming back to my shop and doing the barrel. It has shot 23x’s twice, It shoots my standard load, so I decided last night to remove the barrel and modify it for the nut I made.

At the range this morning, it was rather cold for March, 55 degrees. The conditions were not the best, but with a overcast all day, the tune should stay consistent.

The conditions were straight at us, switching at about 20 degrees from left to right. 5 to 10 mph. Shooting over my standard 4 flag set, they were very readable.

I tuned the barrel with the tuner. The last group in the tuning session was the one on the tan target.

I then hung a score target to do the test. The rifle was shooting really well. I was taking as much as 15 minutes on each Group, catching the condition As perfect as I could for each shot.

The targets speak for themselves. I seemed to be having a pretty good morning. After shooting the groups, I went to the #3 bull, held accordingly, and nailed a wipeout. It always feels good to do that.

The heartbreaker was that #4 bull. I jus flat out missed the velocity of what was a straight at us headwind. That would have been close to a “zero”.

The load is 34.8 grns of H4198, my own 30 caliber 112 bullet, about .010 off the lands.

Conclusion:
If a barrel nut, done correctly, affects accuracy, I could not tell. This darn thing was shooting at a match winning level this morning. This is one of my best rifles, though too heavy to shoot in RegisteredMatches.
The action is the Bat M that I converted to a screw in shroud a few years back. (That was a real project).

Here are some pictures of the barrel in the lathe, the rifle, the range set up, and the targets.

 

[Bamban]

A noble act of selflessness for the benefit of others. Tip my hat, boss.

Back when I shot short range benchrest I don't think you could talk anyone into taking their hottest shooting rifle apart for any reason.

Thank you for sharing.

 

[jackieschmidt]

Here is my standard loading set up at the range this morning. This is exactly what I use in Matches. It looks pretty low tech compared to the stuff everybody post on these Forums. But there is a method to the madness.

 

[Dusty Stevens]

Good job jackie. Great test

 

[jackieschmidt]

Good job jackie. Great test

Dusty, this was really a exercise in doing something just to do it.

It is obvious that this is not practical for our Rifles that are glue ins. This was the first time I ever tried a nutted barrel assembly. It was amazingly easy to set the headspace. Besides, I would take pause to clearance out a spot in the Scoville Stock on my favorite Light Varmint to clear a nut.

But for bolt is, which this Rifle is, it appears that done correctly, the barrel does not know if it is attaché with a shoulder, or a nut.

It would be nice to see a experienced long range shooter do one of these up and see if the accuracy shown at 100 yards translates at 600, or even 1000 yards.

 

[Carl S]

A really nice job Jackie.thank you for your time and effort.very interesting.

 

[DShortt]

Thank you very much for doing this. A very selfless act for the benefit of others. Well done Sir!

 

[DHuffman]

I'm not surprised by your results @jackieschmidt and thanks for the time and effort you put into doing it.
Looking forward to the @AlNyhus test as well as whatever the Montana boys come up with.

 

[Eagle Six]

Jackie, Thank You for performing your test. This proves to me without a doubt that your barrel performed equally well when nutted.

Question: How much torque did you have on the shouldered barrel, and how much torque did you put on the nut for this test?

Hopefully others with the means to do it will jump in, take the challenge, and perform additional tests and publish the results. Like you stated a comparison shooting long distances would be welcome.

If I had the resources I would certainly do so. As @urbanrifleman has stated many times, a one off test isn't definitive, but it certainly is a start. And, I doubt your results will change the minds of those who prefer one over the other.

 

[gunsandgunsmithing]

Thanks Jackie, for using your time and resources for doing the test.

I think there may be more testing for someone to do in regard to the typical contours used with a nut, vs your hv bbl, too. I've been using my own contour for a few years in BR. It's pretty similar to a LV contour, but the logic is that it shows tune more clearly on target..IME, than the stiffer bbls and possibly holds tune a tad bit better. Compromises either way but I have come to prefer it over the stiffer bbl contours. JMHO. And no, we're not talking skinny, whippy bbls either way. I'm not sure where the point of diminishing returns actually is but what I typically use would still be stiffer than most 1.055 breech nutted contours that are relatively straight and smaller pretty much everywhere by some amount.

 

[Dgd6mm]

Shazam! Thank you Jackie for doing this.

 

[jackieschmidt]

Jackie, Thank You for performing your test. This proves to me without a doubt that your barrel performed equally well when nutted.

Question: How much torque did you have on the shouldered barrel, and how much torque did you put on the nut for this test?

Hopefully others with the means to do it will jump in, take the challenge, and perform additional tests and publish the results. Like you stated a comparison shooting long distances would be welcome.

If I had the resources I would certainly do so. As @urbanrifleman has stated many times, a one off test isn't definitive, but it certainly is a start. And, I doubt your results will change the minds of those who prefer one over the other.

I made the nut for this Bat M with a little more wall thickness than most nuts. I also did not cut slots for a wrench. I did this to avoid any distortion due to inadequate wall thickness. Granted, it is not the most aesthetic look, but for this, I was looking for function, The extra meat plus the 4142 Chrome Moly at 38 RC insured that I could tighten the nut at the same level as I do a shouldered barrel. I judge it at around 75 to 80 pound feet.

This is subjective, since the nut is 20 tpi, Regardless, I am a proponent of barrels being tight. You have to place the pieces in tension for the threaded joint to stay secured.

I do not do this stuff to change minds. Regardless of what you do, there is always the “what if” factor. I can see the plus side of the nut, and the minus side. I simply wanted to see if in this single instance if a good shooting Benchrest Rifle would perform as well as a shouldered barrel barrel If secured with a nut.

 

[urbanrifleman]

But for bolt is, which this Rifle is, it appears that done correctly, the barrel does not know if it is attaché with a shoulder, or a nut.

That was my finding.

As a factor, the nut would be about 50th on the list of factors that would effect groups.

Is that action 1.125 x 20tpi?

 

[LVLAaron]

Bat M (what he used) is 1.125 x 16

 

[jackieschmidt]

That was my finding.

As a factor, the nut would be about 50th on the list of factors that would effect groups.

Is that action 1.125 x 20tpi?

See post #298.

 

[urbanrifleman]

Wow. It took me awhile to catch up with this thread. 10 pages or so since I last visited it. I've seen this before a few times over on Sniper's Hide or other forums where type A personalities collide over something like how scopes track or some other variable we deal with in our disciplines.

Let's be real for a second here. We're all type A or we wouldn't be in this game, but that also makes us think in binary and that this should be cut and dried, where a single test will tell us what we want. Conversely, the scientific method takes a much more pessimistic approach to the problem. We need to develop a clear hypothesis, and delineate that against a NULL hypothesis. Once that is determined, we need to come up with a test--preferably double-blind--that will unambiguously prove or disprove our hypothesis.

I would think at the least, we'd need 10 rifles of each design (20 total) identical in every other way and at least 10 shooters each doing ten matches each of at least 10 shot groups. To be double blind, the shooter can't know which rifle is which so some means of hiding the shoulder or nut should be devised. Once all the data are in, a blind analysis needs to be performed and statistical model analysed and if possible, evaluated against the NULL hypothesis (no idea how we would test that) and p-values assigned.

Already, you can see that this is going to be a costly endeavor and will likely never materialize unless we can get the Army Ordnance Corps or SAMMI or someone else with a vested interest and deep pockets involved somehow.

TL;DR: this is not going to be solved anytime soon by just throwing our anecdotes around.

Gene is actually correct.

 

[jackieschmidt]

Gene is actually correct.

Well, I am sure Gene will be glad to tackle it.

I kind of take offense at his “anecdote” comment. When I can take a fine shooting 30BR Benchrest Rifle and do nothing to it except modify it secure the barrel to the action with a jam nut instead of the barrel shoulder, and have it shoot the groups posted, that is a tad more than “anecdotal”.

As I said in an earlier post in this thread, you have to know what you are doing, and have the means to do it.

 

[urbanrifleman]

Well, I am sure Gene will be glad to tackle it.

I take offense at his “anecdote” comment. When I can take a fine shooting 30BR Benchrest Rifle and do nothing to it except modify it secure the barrel to the action with a jam nut instead of the barrel shoulder, and have it shoot the groups posted, that is a tad more than “anecdotal”.

You did a great job on your test.

Amazing machine work. Very cool.

You can get mad, but I think it's misdirected. He's just stating what any industry standard "test" would entail (and he is correct). Nothing really directed at anyone personally. That's my take on it, at least.

 

[AlNyhus]

Thank you Jackie for a great test. No screwing around, no blah, blah, blah...you just did it and let the results speak.

My testing will take a bit more time to complete than yours. We've still got snow on the ground but that will be gone this week.

My barrel is heading to Dusty's for a new chamber (6BR). I'll put it on my Panda HV gun and shoot it. Then Dusty will knock the shoulder off and bring the threads forward for a nut. Then I'll shoot the same loads in it as when it was shouldered. I'm going to do a home brewed joint stability test on both... 'Whack A Mole' style...to check for POI changes between the two styles. Since a good number of nutted barrels are used on PRS and hunting rifles, that may be of interest.

Good shootin' -Al