Will you guys analyze my chamber cast?

M

mofugly13

Guest
I am not a benchrest shooter, but I am a hunter who likes the confidence that comes with a very accurate rifle. A few years ago I bought a used Remington Model Seven in .243, and after firing it, I was very disappointed with the 2 MOA groups I was getting out of the pencil thin barrel. I decided that I would like to rebarrel it to 7mm-08. Not having a ton of money, I bought a take-off barrel from a Model 700, in Remingtons standard 'sporter' contour, that had never been fired. My plan was to strip the action, and do some minor accurizing to it. I turned a mandrel and faced the receiver, and lapped the barrel lugs. I made a thread straightness gage and determined that the factory action threads are indeed true to the centerline of the action, the bolt locking lugs lapped to the action bearing surfaces evenly, so it seems I got a good, "true" factory action.

I have a set of go/no-go headspace gages and with the take-off barrel installed, the bolt closes on the no-go gage. The plan is to set the barrel back until the headspace is correct.

I have done a LOT of reading on this site about chambering and fitting a barrel, and realize the importance of the chamber running as concentric to the bore as possible. With that in mind, I figured I'd make a chamber cast of the take-off barrel I plan to install, just to make sure things were 'all lined up'. The cast I took has me wondering if I should even bother with the barrel I have. It seems that the throat area is not concentric to the bore. Here are two photos of the casting, they are taken 180* apart from each other. In the first, you can see where the throat meets the bore, shown by a circumfrential line around the casting, on the other the line is not there and it looks as if the rifling, or remnants of it, meet the point where the case mouth would be.

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I would like to know your thoughts on using this barrel, keeping in mind that I won't be using it in any competitions, but I do strive for the smallest groups I can get.
 
look like its out of alingment

looking at the photos it look out of true to bore to me !
if i was you i would try it as you have already got it and see how it shoot mite work ok but most likly not ! :(

or sell it and get one that not a take off and fit that
 
chamber

Not quite sure where your concern lies. Anyways you have the barrel already why not use it as a good opportunity to practise your work . What have you to lose ??
Chris
 
I think I will fit the barrel to my action and see how it shoots, and if I'm not happy, I plan on saving for a Douglas barrel. Then I can really practice! That would require an investment in a chambering reamer and a .0001 indicator, and that's what I was attempting to avoid, for now. I was interested in hearing what the accuracy gurus on this site would have to say about the cast. I assume that for you all, a chamber cut like that would be completely unacceptable.
 
Your chamber cast is not fibbing, its crooked. There is also no way
of bringing it back into alignment, as the contour of a factory Rem
barrel has not so much meat on it to allow setback that far.
For the price of a good indicator and reamer, you can buy pre-threaded
and pre-chambered barrels from a number of places. Once every 3rd
blue moon, Rem makes a decent barrel, but I have no clue how they can
be found.
 
Are the pre-chambered/pre-threaded barrels as good as getting a good blank and doing it properly from scratch? I'd really like to be able to rebarrel my M700 30-06 as well, and would like to do it from scratch, and I gotta start somewhere. Maybe I should start with my 7mm-08?
 
There is a fellow who sells pre-threaded & chambered barrels for Remington actions - that are all set up to use a Savage style barrel nut and wrench. Buy a set of headspace gauges and the necessary wrench, change that barrel yourself and be off and shooting!
 
I have seen a few factory barrels like that... I think it is more common than a lot of people think.

I also would not be surprised to see this shoot under an inch.

Get the headspace adjusted and give it a try and let us know...
 
I always get a grin on my face when this topic of switching Rem700 barrels on the cheap comes up. Talking about it one day a guy asked why he couldn't measure the lug thickness and thin it with the disc sander if it was excess headspace because of the shoulder. If he "carefully" took off 3 thou, how much could he be out, maybe 1 thou at the worst. I never came up with a good reason why he couldn't get away with it for a beater hunting rifle.
 
Looks like typical Remington work for the last few years. At one time Remington built some of the finest rifles around. Most of their work receiently has looked like it came out of some third world sweat shop. Shame.

Donald
 
How do they do that???

How on earth do they get a chamber "Out of Round" to the bore ? I can see the base of the case being out of concentricity - but the neck has to follow the bore - Right ? I wonder who is grinding their Reamers, that has to be where it is coming from, no other way to do it, unless it is single point. My Golly !!!

Personally - you have a Tomato Stake, scrap it and start over. There is some very good suggestions above, use one of them and get a decent shooting firearm out of it. Good Luck with the Douglas Barrel . . IMHO . . yuck !!
 
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