Gunsmithing Action thread slop

[MWDG3]

Any of you rifle masters experience slop between the barrel and trued action threads?

Barrel threads cut after action trued. I noticed how perfect the fit is with my BAT, no noticeable slop past first few threads. With the trued action it never really tightens up.

 

[300sniper]

Re: Action thread slop

was the barrel fit to the newly cut receiver threads?

since barrels are typically fit for the receiver in hand, the thread fit should feel about the same regardless if the a bat action or a trued remington.

 

[2156SMK]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MWDG3</div><div class="ubbcode-body">I noticed how perfect the fit is with my BAT, no noticeable slop past first few threads.</div></div>

That is how good gunsmithing work feels.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MWDG3</div><div class="ubbcode-body">With the trued action it never really tightens up.</div></div>

That is how bad gunsmithing work feels.

 

[Duck_McGuck]

Re: Action thread slop

Can you measure the diameter of the threads on your barrel?

Do you know how much material was removed to true your action?

 

[LRI]

Re: Action thread slop

IF:

Your action was worked on and the existing barrel was put back on it then it would immediately explain why/how the thread fit lacks the fitup thats present with your BAT receiver.

A Remington action uses a 1-1/16 x 16 pitch thread from the factory. When gun plumbers recut the threads in the effort to make sure they are on the common center (bolt centerline) material gets removed. How much depends on a number of variables.

Suffice to say your thread is no longer 1-1/16 x 16. It's now "one and something over a 16th x 16". This is where experience comes into play when fitting up the new barrel threads. (which should ALWAYS be done after this kind of work-whether it be a new blank or setting back the existing barrel)

Simply turning the new tennon to 1-1/16 (nominal) doesn't cut it anymore. The major diameter should be bigger and the root of the thread will be bigger. This directly influences the pitch diameter and the amount of flank geometry on the thread. Flank geometry gives you the surface contact between the male/female thread. All of this needs to be factored in for it to be right.

Example:

Last winter I had a client bring in a M700 that had been fitted up locally by someone else. The gun always shot well but it was time to put a new stick on it. The tear down greeted us with a thread that was .04" undersize. The threads on the barrel resembled an Acme thread because the flanks were so short it created a broad flat across the crests.

While the gun always shot well, this was clearly the incorrect way to fit up a tennon. -To the point of being potentially dangerous. If the owner ever accidentally pressured up a load to the point of failure the barrel may have very well shot off the face of the receiver. Considering it was a 7mm RSAUM I'd say he was fortunate to say the least.

SO, long story short and using my story as the barometer: More than likely your gun is fine from a safety/performance perspective assuming all the other work is done right. That being said I would lean toward the side of caution if you've not shot this thing much. Stay conservative with the load work.

Hope this helps.

C.

 

[MWDG3]

Re: Action thread slop

The action was trued and a Bartlein barrel installed. It isn't nearly as sloppy as the factory barrel which I still have, but just not perfect like the BAT.

It shoots under .5" with Federal Gold prone off bipod. For a #3 barrel I'm happy. Just curious of the difference. Both threads cut by the same inexpierenced smith.

Thanks for the input.

 

[Keith Johns]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MWDG3</div><div class="ubbcode-body">
It shoots under .5" with Federal Gold prone off bipod. For a #3 barrel I'm happy. </div></div>


Then there ya go.


Most times, Remington receivers benefit from a slight amount of slop. Not much, but enough to at least feel wiggle.
If you're concerned about yours, its probably looser than it should be, but how it shoots says everything.

Aftermarket actions can be fit a lot tighter than a "trued" Remy. Don't expect the two to be the same.

Just enjoy the half MOA rifle.

 

[300sniper]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith Johns</div><div class="ubbcode-body">

Aftermarket actions can be fit a lot tighter than a "trued" Remy. Don't expect the two to be the same.
</div></div>

How do you figure?

 

[7mmRM]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 300sniper</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith Johns</div><div class="ubbcode-body">

Aftermarket actions can be fit a lot tighter than a "trued" Remy. Don't expect the two to be the same.
</div></div>

How do you figure? </div></div>

wondering the same?

 

[TGagnon]

Re: Action thread slop

I have a 700LA completely rebuilt by one of the best benchrest smiths in the country and it shoots amazing for a 300winmag. But yes there is slop in the threads.
On another note if you read the Houston warehouse article there is a part were he discusses useing barrel slop and an angled mating surface to get a perfectly centered barrel when the barrel is torqued to the reciever. He spoke of putting an angled surface on the shoulder of the reciever and an angle to match on the barrel so that when tightened it self centers.

 

[2156SMK]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith Johns</div><div class="ubbcode-body">Aftermarket actions can be fit a lot tighter than a "trued" Remy.
Don't expect the two to be the same.</div></div>

That depends on the skill of the person truing the receiver.
If you are using full profile inserts or milling the threads, you can indeed fit the barrel just as tight into a trued remington receiver as you do into an aftermarket receiver.

If your receiver threads are not done well, then sure, you won't be able to fit the barrel as tight into them.
Perhaps your personal experience has had you come to the conclusion above.

 

[xs hedspace]

Re: Action thread slop

Hell, way back when I cut my first threads on a barrel, when I was trying it on the receiver, it must have had a chip stuck in the threads, I took off another .002" and it was sloppy. Put a wrap of teflon plumbers tape on the barrel, nice and snug, and the thing would shoot a 1/4" group, if the wind wasn't blowing. PS It was a Wiseman/McMillan barrel, 6mm. If it ain't broke.....

 

[Keith Johns]

Re: Action thread slop

Because aftermarket actions threads are pretty damn perfect. No taper, they're straight and square to the face.

Remingtons are not. Even after "truing" they dont feel as perfect as an aftermarket action(the threads).

I find it hard to believe you haven't noticed a difference between Surgeon or Defiance actions, and trued Remingtons.

We dont open the threads up as much as, for example, chad does.
I have barreled actions trued by several other smiths here. Two from Chads shop. Chads threads were larger and "truer" than ours.



The "tighter is always better" BS, is great for online chit chat. But in practice, cutting tight threads for a Remington is stupid in my opinion... And in the opinion of a few great smiths that don't post here.


<span style="font-weight: bold">Just enough to feel wiggle. </span>

 

[LRI]

Re: Action thread slop

Yet another case of shoe leather in the ol cake hole. . .

If a receiver is properly machined there is absolutely no reason why a barrel cannot be fitted with minimal thread tolerances.

Understand that any statement to the contrary is a big dick sammich shoved down the throat of every competent gunmaker practicing in this industry.

Say something like that to Alan Warner or Jim Borden once. I bet they wont be nearly as gentle as I am.

Especially from someone who a very short time ago was sitting in a classroom learning what headspace means.

Just sayin.

If your (anyones for that matter) threads feel like crap its because you've either exceeded your or the equipments ability to make them right.

Failure to address the defalcation is a reflection of your ability to right a wrong. Nothing more/less.

Taper is a function of:

Tool deflection
misalignment of the bed/chuck centerline in any axis
excessive gib clearances from carriage/bed
excessive bearing clearance on spindle
speeds/feeds
work holding

Surface finish:
tool deflection
cutter geometry
speeds
feeds
work holding
machine wear

C.

 

[Keith Johns]

Re: Action thread slop

There's no reason you need class 3 threads on a barrel tenon.
And IF the action threads aren't perfect, tight threads will cause problems.

The flanks do the work. The face keeps it square/straight.

Threads that are .005" under are great. I wouldn't go sloppier than that but you could.

This stuffs not hard to understand.
Chad not every receiver is perfect. We get a lot of previously "trued" actions in. We're not going to re-true every action for free, or charge then more to do it over.

I'd rather cut the tenon a few thou under what you cut yours at, and build just as accurate a rifle.

Arguing with you about what makes an accurate rifle, I wont do either. Accuracy doesn't seem to be a problem with any of our rifles. In fact the results of our work seems to be contradictory to what you preach all the time.

I care more about the face and <span style="text-decoration: underline">lugs</span>, which you don't seem to. Your receiver lugs didn't seem to be trued. And the bolt was completely untouched from what I could tell.


OP, enjoy your half minute rifle.

 

[LRI]

Re: Action thread slop

When where have you ever heard me preach about what is critical to rifle accuracy?

I tell people what we do. That's about it. Your left to judge for yourself.

As for lugs. Every receiver is machined. Bolts rarely are. I will stand by that 100%. Its because it doesn't have a choice. The lugs, face, ID bore are all cut with the same tool at the same setup/time. It has no choice.

Btw, just how are you checking this? With your midway brand calipers or your fully equipped metrology lab?

Understand, you brought my name into this bub. I didn't say shit till now. I get it, your new and want to make a name for yourself. Competition is great and I openly embrace it. Build a better gun, go for it. But if your going to run your mouth your foolish if you think there wont be a response from someone you single out. Especially with almost zero experience.

A little while ago you were limited to sticking gear shifter tac knobs on bolt handles. I will freely admit that in that arena you'll likely hand me my ass. I don't do many and I loath doing it as a general rule. Its about as exciting for me as changing oil.

Anyway. . .

Because it ultimately matters little when the ass end of the bolt is trying to climb over the sear on the trigger. Only the lower lug is touching anyway.

Nevermind that a spring loaded plunger is trying to poke the case in the ass at 12 o clock when the thing is in battery.

It don't mean squat cause the moment the striker hits the pressure is going to straighten things out.

I've sat and cad modeled this out. +.005" means an angular deflection of .054*. Thats about. 00015".

Find that tolerance on an airplane or spaceship. You wont in very many spots.

Accuracy claims are like measuring dicks. Its ego. Our guns have won stuff in a variety of planet level arenas. That means a great deal more to me than a half minute or better.


Last, thread fits.


Br guys change barrels like socks. They snap them on/off like tires at a race.

Guns hold group size all day. Group center however is another story.

Sit with a calculator and figure the lbs of kinetic energy develped when a gun goes bang. Now factor in the lever effect it has out towards the muzzle. All of this transitions through that 1 inch long threaded joint.

Maybe it doesn't matter at 100 yards. Our guns are rarely shot at this distance by the end user. You start holding 1/3rd minute elevation at 1k and you quickly learn to leave no rock unturned.

Its also a matter of learning which rocks really matter.



You go on and tell yourself that thread fits don't matter. Makes my job that much easier.

 

[Keith Johns]

Re: Action thread slop

And we didnt build the OPs rifle. Incase it seemed that way.
Just dont want the guy worried about his sub half MOA rifle someone out there built him.

 

[2156SMK]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Understand that any statement to the contrary is a big dick sammich shoved down the throat of every competent gunmaker practicing in this industry.</div></div>

He Doesn't.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">You go on and tell yourself that thread fits don't matter. Makes my job that much easier. </div></div>

Exactly.

I find myself lapping barrels into receivers quite often and boy do they fit nice...

 

[MWDG3]

Re: Action thread slop

I'll be spending more time with this Howa 308 once back from melonite. Plus my smith added an Elite Iron brake with no slop at all. Need to work up a load for next years elk hike.

This .4" group is pre-brake.

 

[300sniper]

Re: Action thread slop

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Keith Johns</div><div class="ubbcode-body">
The flanks do the work. The face keeps it square/straight. </div></div>

the leading flank of a vee thread doesn't do anything other than adding strength ot the thread itself. it doesn't center anything. if there is ANY clearance between internal/external pitch diameters on a vee thread, the leading flanks won't even be making contact.

the shape of the opposing vees at the trailing flank when the fastener is tensioned is what centers and attempts to keep the joint straight. if either shoulder is not square to the thread axis, the threads and shoulder will be fighting to conform, regardless of class of fit.

and a fyi, if you open your machinery's handbook, you'll find your .005" clearance for a 1-1/6"-16 falls into either a class 2 or 3 fit.