Pre bore the chamber results?

[dakor]

By design, a reamer is designed to finish a hole, not drill one! This is the most basic of machine shop knowledge, as in machining 101. You need to find some smarter friends. Lol!
Paul

Really I had no idea that is what they are for thanks for the information. Oh but wait do your barrels come without holes?

The ones I order come with holes in them already and that is what the reamer is reaming out.

Call up JGS or PTG and let them know that their reamers are not made to ream a barrel bore as is and that you need to drill the chamber area out before you use it. let me know how that goes.

 

[Edd]

I'd appreciate any in-depth comments about the use of a bushing.

A. Weldy

If you pre-bore, the reamer body is guided by the pre-bored part of the barrel. The only thing a bushing does is restrict the flow of oil to the reamer.

 

[Judd]

That with the fact you are making a lot of assumptions about the bore that you cannot prove

I know guys that cut chambers between centers that have good results. Hell I even met a guy that worked for a big arms company that when they chamber their 50 cal bmg's they are between centers and when the reamer engages they open the steady rest and let the reamer float the bore. Their rifles shoot so what does that tell you?

Question…if you measure the two points you do and then back up 2” (most cartridges have 2”) and measure there, if that is straight or not would prove OR disprove his assumption. I’d say they are all different based upon my experience...meaning some will be and some won’t be.

Second…theoretically, if that isn’t straight with your two measurements (to the 2 tenths) how do you fix it with your method?

As to the second part of your post above…what that tells me is there are many ways to skin this cat…I am not knocking your method or the predrill method, I’ve seen both shoot extremely well.

I am shocked you don’t clock the muzzle to your action with how you do it…seems eventually you’d run into a barrel that would run out of L/R scope adjustment and break Dave’s number one rule…the phone is ringing.

 

[Alex Wheeler]

I use the much discussed method of drill, taper bore etc because
I'm confident and comfortable with it. This yields good results considering my skill levels and machine quality. I don't pretend to think this is the best method for all----you play your game and I'll
play mine. BTW, I don't oppose learning improved methods.

@butchlambert has raised the question----why use a pilot bushing
if you taper bore ? Somehow I picked up early on that the bushing
helped support the skinny end of the reamer.

I'd appreciate any in-depth comments about the use of a bushing.

A. Weldy

The bushing can be useful or harmful. If you dial the throat and muzzle, Id be weary of the bushing. The section of bore the bushings in is not dialed in. If its running out then it will bring the front of the reamer along for the ride and you will not have a throat thats centered. From one barrel to the next you would see more or less of this effect. Thats the idea behind the boring, you decide where the reamer goes. Not the pilot bushing. But, the bushing also supports the front of the reamer. In some cases with very long throats or in 5 groove barrels this is desirable. But you want the bore the pilot is in running true. In a perfectly straight barrel all methods would result in the same outcome. But I have yet to find a perfect one.

 

[Carl S]

By design, a reamer is designed to finish a hole, not drill one! This is the most basic of machine shop knowledge, as in machining 101. You need to find some smarter friends. Lol!
Paul

That's correct Paul 100%.a reamer is for reaming not drilling.

 

[Carl S]

I'm not saying one method is better than the other.as I've said before people do things differently.if one sets up the barrel in the 8pin spider and dials in the throat and breach so that section of the barrel is true and the muzzle floats.the bushing in the bore has a little movement the bushing on the reamer has a little movement and if its a solid piloted reamer chances are it will have quite a bit of movement from barrel to barrel.then put it in a floating reamer holder or a fixed holder-assuming your tail stock is in perfect relationship with your spindle bore.don't forget your going to cut your chamber not all that close to your head stock bearings..I'm sure there is some overhang and then you start to ream away.may be there is a chance of a few variables to contend with!.i chamber barrels for a local dealer and he normally supplies the blank and reamer..various calibers the reamer is almost always a solid pilot and a loose fit in the bore.i dial muzzle and throat.drill pre bore,ream and the interapid shows 2tenths max run out.its so consistent..would I run that reamer straight in..no way.no matter what set up I used.ive found this set up and pre bore 'fool proof'.chambers come out straight and true.

 

[shortgrass]

I'm not saying one method is better than the other.as I've said before people do things differently.if one sets up the barrel in the 8pin spider and dials in the throat and breach so that section of the barrel is true and the muzzle floats.the bushing in the bore has a little movement the bushing on the reamer has a little movement and if its a solid piloted reamer chances are it will have quite a bit of movement from barrel to barrel.then put it in a floating reamer holder or a fixed holder-assuming your tail stock is in perfect relationship with your spindle bore.don't forget your going to cut your chamber not all that close to your head stock bearings..I'm sure there is some overhang and then you start to ream away.may be there is a chance of a few variables to contend with!.i chamber barrels for a local dealer and he normally supplies the blank and reamer..various calibers the reamer is almost always a solid pilot and a loose fit in the bore.i dial muzzle and throat.drill pre bore,ream and the interapid shows 2tenths max run out.its so consistent..would I run that reamer straight in..no way.no matter what set up I used.ive found this set up and pre bore 'fool proof'.chambers come out straight and true.

Ever look at the rifling where the fixed pilot was?

 

[jackieschmidt]

I think we all stopped listening when you said we can't bore a straight hole.

Decades upon Decades of accepted machine shop practice thrown out the window.

Gosh knows how many bushings, liners, couplings, etc we have bored at my Shop over the past 6 decades…..….with a boring bar.

I had no idea that it was impossible.

 

[dakor]

Decades upon Decades of accepted machine shop practice thrown out the window.

Gosh knows how many bushings, liners, couplings, etc we have bored at my Shop over the past 6 decades…..….with a boring bar.

I had no idea that it was impossible.

Think of the oxymoron statement that was made. "I think we all stopped listening when you said we can't bore a straight hole"

So you guys can bore a straight hole but Bartlein, Benchmark, Brux, and so on cant. Now just think about that for a minute. I am sure that micro boring bar you are using on a hornet or 223 size case has no flex on it. Just a question what are you holding your reamer with?

As for clocking barrels as the videos show its a myth. That thing is flexing while the bullet is moving down the bore but I suppose I am wrong on that to right?

If you are running out of adjustment I would say its from your base screws are drilled and tapped off center it has nothing to do with a curve of a bore. The bore is not curved when the trigger is pulled.

But I am sure I will get told I am wrong about that as well. I wish I still had the old benchrest magazines that I had before a flood took them. One had an article that had some top notch smiths at the time saying not to use a roughing reamer just use s finish reamer to cut the chamber start to finish. Guys that still hold records today.

Just going to ask anyone have any first place trophys or shooters that have any or any records?

I mean the guy I learned from has 149 first place plaques on the wall and drove Tim at Broughton barrels nuts for all the barrels he got for free for his first place finishes, was the first shooter chaired by other shooters but what the fuck do I know.

Your method is obviously better and I should just suck at the tit and accept it.

 

[swd]

Jezus let’s just beat a dead horse…

 

[WSnyder]

Jezus let’s just beat a dead horse…

For sure, 10 pages and hundreds more just like it scattered all over the Internet the last 25 years or so

 

[Carl S]

Ever look at the rifling where the fixed pilot was?

I always check the chambers with the bore scope and i no Mike definitely will when he gets them home.if there was any flaws he would be on the phone.if i didn't pre bore and use the muzzle flush system may be I would have marks on the rifling where the reamer potentially goes in on the piss and cuts off centre..may be I would if i used the reamer as a drill and not start it in a true pre bored hole.im not saying my way is correct but it works for me and it doesn't make the phone ring.Regards.

 

[jackieschmidt]

Think of the oxymoron statement that was made. "I think we all stopped listening when you said we can't bore a straight hole"

So you guys can bore a straight hole but Bartlein, Benchmark, Brux, and so on cant?

Well, since you asked, when it comes to the ID‘s of rifle barrels, no, they can’t.

(hint. ….the ID of a barrel is not bored. It is gun drilled, reamed, rifled, and lapped.)

 

[STS]

So you guys can bore a straight hole but Bartlein, Benchmark, Brux, and so on cant.

They are not boring a hole, they're drilling it. And no, the holes they drill are not straight.

 

[dakor]

I know how the barrel making procese works I have seen it first hand years ago when I was in a shop of a man that was cut rifling barrels before it was cool.

Bartlein also has some nice videos on the youtube if you want to check out how they are making them.

 

[liljoe]

Is this mike in co or stephen perry?
Joe

 

[Judd]

As for clocking barrels as the videos show its a myth. That thing is flexing while the bullet is moving down the bore but I suppose I am wrong on that to right?

If you are running out of adjustment I would say its from your base screws are drilled and tapped off center it has nothing to do with a curve of a bore. The bore is not curved when the trigger is pulled.

But I am sure I will get told I am wrong about that as well.

I’m not that guy…mainly because if I haven’t done it, I don’t know. I’ve indicated and chambered your way but always clocked them, most of the time up but did recently clocked one down as an experiment. I noticed no change fwiw.

Interesting, thanks for sharing your experience. I’ll likely try one at some point just to see if I see a difference.

You’ll find this group is a good group with a wealth of information, especially if you don’t come off so defensive/offensive. But like anywhere else in life, we ain’t all going to agree…it’s about sharing and having an open mind to learn something new for me.

 

[dakor]

Is this mike in co or stephen perry?
Joe

K&P when he was in New Rockford North Dakota.

 

[dakor]

I must have missed the joke no idea who you are speaking of. I thought you were asking what barrel company I was able to watch at but I guess you were insulting me.

Anyway this will be the last thing I say in this post. I have rifles to build.

For all the kind people that insulted me bless your heart.

 

[LVLAaron]

Guys! I did it! I bored a concentric hole!