Throating reamer effect on accuracy

[carlsbad]

I'd like to hear peoples thoughts on any problems added by use of a throating reamer.

If you have a short freebore chamber reamer and you then extend the throat with a throating reamer have you introduced any inaccuracy?

If you are building a match rifle would you always opt to order the reamer with the required freebore for the round?

Or with proper care is a 2 reamer chamber just as good?

I don't expect us to all agree on this issue so please respect the opinions of other.

thanks,

--Jerry

 

[boltfluter]

Any time you do something in 2 steps that can be done in 1 you run the risk if inducing concentricity errors. Especially when it applies to machining practices. Just my personal opinion, but something I feel strongly about.

Paul

www.boltfluting.com

 

[eddief]

World record barrels can and have been chambered both ways. Depends on the skill of the individual who is chambering the barrel.

 

[ab_bentley]

I've never noticed it, but then again I groundhogs, not matches.

Adam

 

[carlsbad]

I like both answers so far.

I also got a PM from a member who wanted to ensure he avoided conflict stating he had had good results with the 2 reamer method.

--Jerry

 

[spclark]

I had great results ordering a minimum-throat custom reamer along with a throater; 'smith said 'it wouldn't work' if I didn't use a lathe with the throater.

That barrel went on to tie the NRA Senior 1,000 yard sling (and open sights!) record last June, 200-15x:

 

[Wirelessguy2005]

A few months back there was a guy with a 6mm barrel that he chambered in 6 dasher only to discover that his reamer didn't have enough freebore for the bullets he wanted to run. According to what I was told he ran a throating reamer in to lengthen the Freebore and while doing that wiped out a few lands. The barrel didn't shoot very well after that. I am sure someone with experience and skills can pull off this job but it's probably best avoided if at all possible.

 

[ab_bentley]

All this talk, it should be said, if you don't build a dedicated throating tool, this should be done during the chambering process, in my opinion.

Adam

 

[Terry Altom]

I assume we're talking about the PTG unithroater that someone other than a gunsmith would use on their own barrels.

 

[carlsbad]

I assume we're talking about the PTG unithroater that someone other than a gunsmith would use on their own barrels.

Or a throating reamer such as those made by Manson or Clymer and available through Brownells. I am assuming it is done during the chambering process with the appropriate tooling to keep it concentric. --Jerry

 

[ab_bentley]

 

[Terry Altom]

I think this is a very good distinction to make. During chambering by the gunsmith or by the owner later on.

 

[Ggmac]

As you can see , many answers and I think MANY variables . If you need a longer throat , you only have one other choice . Pm me and I'll email you the way I extended my barrel life and throat . It was over 20 yrs ago but I still use those reamers .

 

[Hal]

A few months back there was a guy with a 6mm barrel that he chambered in 6 dasher only to discover that his reamer didn't have enough freebore for the bullets he wanted to run. According to what I was told he ran a throating reamer in to lengthen the Freebore and while doing that wiped out a few lands. The barrel didn't shoot very well after that. I am sure someone with experience and skills can pull off this job but it's probably best avoided if at all possible.

When using a throating reamer you need to have a stop or you'll end up with a smooth bore rifle.
Adam's set up looks slick.

Hal

 

[DaveTooley]

The purist in me says it has to have an affect on accuracy. The businessman/craftsman says I have seen it on the target yet. I do it when I'm chamber the barrel as well as a dedicated setup to do it while the barrel is on the action. Unless you have a really screwed up setup the reamer is going to the middle of the bore.

 

[carlsbad]

Thanks guys. Real world experience is what I was looking for.

--Jerry

 

[spclark]

By hand is another story. I still think if done carefully your fine.

Exactly.

Using a piloted throater, fitted with a bushing to keep the back end nicely centered in the case body's chamber, it's not hard to do a 'four-square' job of moving the lead forward.

What's tricky is knowing how much force to use to advance the lead to where you want it to end up, unless by some means you employ a positive stop.

My project was inspired by a French cartridge design. During development conversations with the designer (RGC here) he allowed that it's commonplace overseas to use throaters to 'tune' freebore on short-throated chambers... by hand.

 

[tenring]

Just a little off this topic. I wanted to touch the lands with heavy .224 bullets in my Savage 12. Made up a dummy round, took it to my smith and asked him to extend the throat about .050" for that length round. He did so. Now , to my dismay, the tip of loaded rounds contact the port and will not eject. My only alternative is to start over with a new chamber or jump bullets. .

 

[spclark]

Now , to my dismay, the tip of loaded rounds contact the port and will not eject. My only alternative is to start over with a new chamber or jump bullets...

Yes, one needs to account for the length gains when doing this kind of modification, anticipating any unintended consequences, but I don't understand why you need to "start over" if this problem is only with loaded rounds not ejecting?

Unless there's a cease-fire called & you have to clear your rifle, why / how often do you need to eject a loaded round from your chamber?

All my bolt guns allow removing the entire bolt from the action fairly easily. I've never owned a Savage so I don't know whether this would be a possible recourse for you.

 

[msalm]

I've made a couple chambers for personal rifles with multiple reamers, one was a 25-284 made with a 6mm-284'reamer, followed by a 25 cal neck and throat reamer that didn't have a large enough neck diameter for the resized brass so that was followed with a 25-06 reamer to open the neck some more.... After all that, the lightweight (win featherweight profile barrel) shoots like gangbusters and is one of my favorite hunting rifles. Shoots well under 3/4 MOA with a 1.75-6x scope mounted and weighing about 7.5 lbs all up.