Pre threaded and short chambered barrel ???

[hottshott526]

Hello,

I have a question about pre-threaded, short chambered barrels and the outcome of a DIY job.

I'm looking to build a Rem .260, only because I can't find an off the shelf Rem action rifle in my price range.

I have a Rem 700 trued action and stock already as well as a barrel vise and go and no go gauges.

So...

Is it possible to buy a Shilen Pre thread/short chambered barrel and PTG reamer and cut the last few .001's of the chamber by hand?

I know that if the reamer used to rough cut the chamber isn't the same dimensions as the finishing reamer that I could run into problems.

But how likely is this to happen? Rings in the chamber from different diameter reamers?

Is this even worth the trouble and should I scrap the idea and just save the money for a real "Smith" to do it?

I'd still buy the un threaded barrel and reamer if a Smith were to do it.
The only extra cost would be to the Smith but I'd like to try on my own IF it's advisable.

Thanks
Brian

 

[Preacher]

Most prefit chambers are cut short with a finishing reamer, but may not be a 100% exact to what you may use to do it the rest of the way.
The threads are usually exactly what they should be..
Lots of short chambers are finished off by hand....
Last I knew Douglas cut the chamber full length and left the shank short, and thats easy to deal with, and no reamer problems...

 

[mudduck]

Well I am going to finish mine tonight. My buddy's already done four or five. No problems yet doing it buy hand. All shilen short chamber barrels.

 

[fguffey]

Normally the advise is "Check often because no one knows how close they are to finishing" & "No one knows how short the chamber is". In the real world when someone says that I have to respond with "You are joking, aren't you?

Knowing when to stop and how far the reamer must be advanced to finish is the beginning of knowing something about 'what you are doing'.

You have a go and no go-gage. You have a barrel with a short chamber. Perfect. We all know the barrel will not screw in and seat against the shoulder with the go-gage in the chamber, for practice, install the go-gage, screw the barrel into the action until it stops. After lightly screwing the barrel into the action until the go-gage holds it off measure the gap between the front of the receiver and barrel shoulder (with spacer http://www.ebay.com/sch/i.html?_nkw=remington+700+recoil+lug ). The width of the gap will allow you to determine the length of the short chamber and how far you need to ream.

I speak for no one else, I would lengthen the chamber before installing the receiver/lug. I would also measure the distance from the front of the receiver to the bolt face. The go-gage can be used in the chamber to determine case head protrusion.

I have a book by JOHN L HINNARD, it is called "The complete illustrated guide to precision rifle barrel fitting", it would have been nice to have started with the book in the beginning.

F. Guffey

 

[idahoorion]

many trued actions have the barrel threads enlarged to true them a standard remington thread in these is likely too small. check it out.

idahoorion

 

[watercam]

Having done a few with success I still feel that the rifle will be more accurate with a barrel fitted to the action at hand. Threads and chambers will vary from action to action and a gunsmith worth his or her salt will cut the threads to just fit and cut a truer chamber in the lathe than we can by hand. The difference in price these days amounts to about $150-200 over a pre-fit.
Try it once and see but make sure you understand what tolerances you are dealing with and what the process is. Head space tolerance is +/- .0025" but you are aiming for +/- .0005". Check often and clean the chips out before you measure.

 

[Riesel]

I know I'll probably catch 'ell for this but watch a you tube video with Larry Potterfield doing this and then catch as many others that will show up. Watch and study what they do and separate the wheat from the chaff. If, after watching these videos you don't feel comfortable doing it, pass. It will save you from stress and could save you money in the end. On the other hand......... I have done quite a few of these with mauser actions and bennet barrels and have been pleasantly surprised by the results. Go slow, measure often, clean chips with fluid and air, and keep everything well lubed. A good reamer rental company can supply a more than satisfactory reamer and keep your cost down. Always remember to included the recoil lug (It is standard thickness, isn't it?) Ok, I know, I asked for this and I will respect your decision.

 

[hottshott526]

Thanks for the informative replies. I've never been down this road before but am willing/wanting to try it

The action is from a buddy that went to gunsmith school. He built a rifle on it while in school. He told me that the threads are still factory so a pre-fit should still work.

The lug is standard

I ordered a Shilen pre-thread/ short chambered barrel, reamer, reamer T handle and a few other gadgets.

I've watched every video about the subject that I can find.

The 1 different thing I noticed between the videos is

Some do the reaming with the barrel vertical in a vise and some do it horizontal.


My thinking is that vertical might be better

1
to get a more centered feel of the reamer without adding any angled cant to the reamer handle

And

2
to let gravity help in the forward movement of the reamer

Do any of you think it matters??

If all goes well, could .5 moa accuracy be expected with handloads?

Thanks again for the info,
Brian

 

[Riesel]

I did most of the reaming while the barrel was in a vertical position and pointed into a trash can for the chip flushing and air. I think you get a better feel on what you are doing and remember you're not taking out much, have everything torqued up tight and check often with the go gauge. When it'd getting close the bolt will start to lock up and you will see it in the position of the handle. .5 MOA from the rifle should be quite doable if you do your part. Good luck with your project and we hope to hear back from you.

 

[Timgunner]

Before I purchased a lathe I built a .308, two 7mm Rem mags, a 25/06, a 300wsm and a 6.5-06, using this exact method. The only issue is I've had is different measurements from differnt barrel makers. I have bought mostly Shilen pre thread short chamber barrels and all worked fine. I have done one McGowen and the "short chamber" was not so short; infact it headspaced perfect without needing the reamer. Pure luck there but it could have easily been too long which would have created a problem. Every one of these rifles shoots .5" groups with hand loads. I prefer holding the barrel in padded vice jaws pointing down into a can. I use an air compressor to blow out the chips and cutting fluid every 20 turns or so. I check often with the go gauge and always inspect the chamber with a flashlight to make sure there is nothing in it before inserting the go gauge. I like a slight crush fit for headspace so I keep several dummy rounds handy to check when the headspace is getting close. Often the bolt will close on the brass long before the go gauge. hope that helps. I got started by reading an article at realguns.com on building a rem 700. It might still be on that site I don't know. Good luck and be meticulous it will pay off

 

[hottshott526]

Which type of reamer would be best for this project

Solid pilot or bushing.

I bought a solid pilot, thinking that the chamber is already cut and I'm just finishing it off, but again I'm entering uncharted territory.

I now have all the tools to do the project and plan on doing it this weekend.

Is there any way to tell what the freebore is before I start cutting? Just wondering because I want to shoot the 140/142 class bullets.

Thank you all again


I will post the results of how it went and some groups when I get out for the trial run.