Does slop between barrel and action threads affect accuracy?

[Mram10us]

My goal is to honestly show what I go thru with rifles so I and others around me can learn and get better. I don't post the best 3 shot groups I've ever shot at 1000+ to pretend I'm Gods gift. I post the whole session so guys can see what the load testing is actually doing. This doesn't define me like it does others. That said, it is my passion because it gets me to that one shot a year on a mulie that I absolutely love

 

[25WSM]

I think the word slop is what is confusing people here. I make my barrel tennon .001 to.002 smaller than the receiver. When the receiver will just about go on by hand without force I dial in another .001 and cut it again. If the receiver goes on smoothly with no force it's done if it has any felt resistance going on it gets another . 001 until it goes on smoothly. I don't call it slop. It's the amount of play I believe it needs to face up correctly. When you screw the receiver almost all the way on and you can't move the rear of the action side to side a little then when the 2 faces match up the shank is going to be forced to one side and create tension. The only actions that can have a tighter fit are custom actions that have perfect thread alignment to the bore and face. Or if you fully blueprint the receiver which would include recutting the threads and face. Even one these perfect receivers I want my barrel to go on with no force.
JE the example of a tight thread holding the barrel from moving side to side on the face has no merit. A proper thread does not touch the root of the groove which means your counting on thread faces to hold the barrel from moving to the side. When you tighten the barrel in a vise the threads pull tight and the back of the threads don't touch any more. It's all on one face of the threads. And the two angles pulling on each keep it centered. A slightly looser thread would just have . 001 to . 002 less face to pull against. And as I stated before I've seen guns that shoot lights out that had barrels fitted so loose I couldn't beleive it. Alot of custom benchrest Smith's keep your dimensions so you can order another barrel without sending your rifle to them. They are not cutting a thread so tight that it might not go on by hand. They have a little play in them. I've been around them way too much to know. I build 100/200 yard bench guns as well as 1000 yd bench guns. And know many Smith's from shooting compatition and we all talk shop. I enjoy my conversation with them because we all know what each other are saying without explanation. This question has come up before and you know where I stand on it. I'm not alone on my position.sorrh for the long post.
Shep

 

[J E Custom]

I totally agree that the OD of the tenon should be one or two thousandths smaller than the thread root so galling doesn't occur. but I don't cut the depth of the thread anymore than required to assemble. The better the fit the more support the receiver
gives the chamber, plus the alignment is better.

Tooling and Technique has to be very good to get a proper finish on the thread faces and if it is, it will fit perfect with no slack what so ever. the amount of slack needed between the threads is a matter of opinion and my opinion is that they should be as tight as possible for assembly to keep everything as close to perfect as possible.

Like you, I have seen some rifles shoot really well with lose fitting threads as long as other things are very true, but I have seen a larger percentage of rifles shoot well that All parts of the assembly were precision.

Besides there is a certain amount of pride in cutting well fitting and good looking threads besides the benefit of precision work.

Just my opinion

J E CUSTOM

 

[25WSM]

I totally agree with you about the precision of the thread. The angle of it has to completely match the receiving thread so the faces have full contact. I find when they match perfectly the barrel tightens with less of a turn on the wrench. I get that personal sense of pride in doing it right. And just as the argument about chambering between centers or in the headstock. This will be the same.
I am a very results driven person and as long as my rifles shoot one hole I will build them the way I do. And I know someone can do it completely different and achieve the same results. One constant in all of this is things need to be straight and true to the center line. How you achieve this doesn't really matter. And JE I seldom find any fault in your post and that is why I give you likes very often.
Shep

 

[J E Custom]

I totally agree with you about the precision of the thread. The angle of it has to completely match the receiving thread so the faces have full contact. I find when they match perfectly the barrel tightens with less of a turn on the wrench. I get that personal sense of pride in doing it right. And just as the argument about chambering between centers or in the headstock. This will be the same.
I am a very results driven person and as long as my rifles shoot one hole I will build them the way I do. And I know someone can do it completely different and achieve the same results. One constant in all of this is things need to be straight and true to the center line. How you achieve this doesn't really matter. And JE I seldom find any fault in your post and that is why I give you likes very often.
Shep

Thanks Shep
I sometimes think that my quality standards fall on deft ears with many and many times get beat up for trying to get everyone to there best. I know many gunsmiths that feel the same way as you and I but there are many that just don't seem to care
and are not willing to go the extra mile.

I read horror stores all the time and feel bad for the shooter that has ended up with poor workmanship. So I keep plugging along.

I cant make others do there best but I can recommend that they do and try my best to explain one way to do it so they will see the benefits.

J E CUSTOM

 

[Tank308]

I was really liking the answers posted till the personal accusation was made. I think we all agree that using the word Slop isn't a good tolerance term. I'm glad it was edited out. I'm not a smith but I like to be able to know what I'm getting when I hire one. I hope the tread still will provide more information. Like on the torque specs. Are they the same for CM and stainless? Does it change if I want a stainless barrel on my cromemolly receiver?

 

[25WSM]

I personally don't change the torque specs from differing metals. I do however change the specs for target guns and hunting rifles. Target rifles are having many barrels put on and taken off by the owner using a small barrel vise clamped to a table top and an inside the rails action wrench. So these see very little torque compared to what the factory values are. I think Remington uses like 1 to 2 million ft pounds to put barrels on. Yes that is a joke that gunsmiths will get. To say the least they are on there hard.

 

[25WSM]

Sorry hit the wrong button and sent the post too soon. I personally use 40 ft pounds for my rifles except target guns. It will never shoot loose. Even if you put a barrel on hand tight and put 5 rounds through it you will need a wrench to get the barrel back off. Now if you get a rare left twist barrel you will need to go to at least 40 pounds. I really don't know why anyone would want a left twist. If anybody knows let me know what I'm missing. So my short answer is 40 ft pounds on all my rifles regardless of the metal type. I just don't think any tighter is better. Look at all the bench guns shooting zeros and 1s and there on the action with less than 40 pounds. I know you are going to see every number under the sun and that's ok. 60 to 80 to 100 are all ok. I just don't think it's necessary so I don't.
Shep

 

[Mram10us]

I was really liking the answers posted till the personal accusation was made. I think we all agree that using the word Slop isn't a good tolerance term. I'm glad it was edited out. I'm not a smith but I like to be able to know what I'm getting when I hire one. I hope the tread still will provide more information. Like on the torque specs. Are they the same for CM and stainless? Does it change if I want a stainless barrel on my cromemolly receiver?

Threads get derailed a lot when some want to make it seem that they do things better than everyone else. Sometimes derailed when they cannot grasp what the op is meaning and would rather argue semantics.

I guess I'm different. I try to understand what the op is getting across and add something constructive rather than argue semantics.

 

[sturner]

I personally don't change the torque specs from differing metals. I do however change the specs for target guns and hunting rifles. Target rifles are having many barrels put on and taken off by the owner using a small barrel vise clamped to a table top and an inside the rails action wrench. So these see very little torque compared to what the factory values are. I think Remington uses like 1 to 2 million ft pounds to put barrels on. Yes that is a joke that gunsmiths will get. To say the least they are on there hard.

And they use red lock tight too

 

[Grizzhunt]

Honestly I wish I had the video personally but I don't. I had my cooper model 21 re barreled with a proof research. My smith took a video of the factory barrel coming off and it was pretty **** loose. His Instagram is Nielson_custom_rilfes. The video is on there if you want to scroll down mid way through is page and find it. The factory battle shot great till it didn't anymore. It was used when I got it so I have no clue how many rounds went through it, I put probably around 600 after I got it. But it would shoot under half inch pretty much all day long.

 

[bigngreen]

There are a few guys that have chases thread type and fit down the rabbit holes, I've seen more issues by trying to thread to tight than sloppy. Some where Wheeler has a picture of the tenon from a barrel he pulled from an amazing shooting gun, holds records, it was so loose its a wonder it tightened up it had like a .040 narrow spot in it and was kinda a mess. I used to thread like i was trying to prove something, only causes heart ache for no gain over a quality thread that easily does its function.

 

[25WSM]

Yup
Shep

 

[birdiemc]

I have to say the rifle I just did, my first ever, I would be terribly embarrassed to let any of you guys see the threads. They are rough and loose, enough that it had me considering just chopping it off and starting over. I picked up a little chatter on my second to last pass and instead of trying to clean it up with a file, i just tried to cut through it, but it was too deep and i just botched the whole job...but i decided to go with it to see, and surprisingly enough it shot just as good as any rifle i own, and with factory ammo. While i know that is not the precision you all are after, it is sub moa so far and was a great learning experience for me.