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6.5 X 284 Reamer Drawing for Berger 140 VLD

I am getting ready to order a 6.5 X 284 reamer from Dave Kiff at Pacific Tool and Gage.

The reamer is going to be set-up for Lapua brass and Berger 140 VLD's. Throat,leade, freebore, or whatever is the correct term) will be so that the bottom of the boattail juncture is 'at' the brass neck/shoulder juncture.

I know that PTG has made this reamer many times, and trust that Dave knows exactly what I want and will get it right. When we talked he said that I wanted .188 freebore. However, if one of you out there has a drawing of your reamer set up for this bullet brass combo, I would sure like to get a copy just to verify that the drawing PTG sends for approval is correct.

Ted
Tconway@prou.com
 
A .188 free bore should be fine assuming your throat angle is one and a half degrees, since the appropriate freebore length also depends on what throat angle you are using. I have a JGS reamer with a .175' free bore and a one and a half degree throat angle, and it is excellent with the Berger 140 VLD's. Mine has a .296' neck and I neck turn my Lapua brass to .293'. The body on mine works very well with Lapua brass too. If you start playing around and tighten the body up to try to 'hug the web' you can 'paint yourself into a corner' and wind up having to use small base dies so be careful trying to go too tight with the body,i.e. Lapua brass is 'fat' and is usually at max SAAMI specs). I never liked the .125 radius on most 6.5 x 284 reamers at the junction of the neck and shoulder because if you use something like a Reddding Type S. FL bushing die, it only has a broken corner in the die at that spot and having a big radius in the chamber makes your brass blow out there only to then be crunched in again by the die,not good for case neck runout), so I tightened up that radius some for that reason,i.e. to a .060' radius).

See attached reamer.

Good luck!

Robert Whitley
 
Robert and Dennis,

Thanks for the reply.

A couple of more questions. I am not trying to get 'fancy' on the reamer design. And I am sure that Dave Kiff knows exactly what he is doing. Rather I am just trying to verify that I have communicated to him correctly as well as trying to understand the theoretical dimensions.

If I seat a bullet into a case and place the bullet full diameter boattail juncture where I want it in relation to the case neck shoulder junction, the bullet will contact the lands at the axial location where 1.5 degree taper has reduced the chamber diameter to the bore size,i.e. lands are at full height), which is basically the reamer pilot diameter? I assume that the reamer pilot diameter is 'slightly' smaller than the distance between two opposing lands?

Ted
 
Ted

You're getting a little complicated in your discussion there. The bullet will make contact with the lands somewhere in the taper of the throat, wherever it does, based on the configuration of the front end of the bullet and your chamber,and the same bulllets can and do vary lot to lot, etc. so there is always some 'fudge factor' in all of this).

What I understand you are communicating is you don't want the bearing surface of the bullet back in the case, but presumably not far up in the neck either,i.e. best is typically just ahead of the neck/shoulder junction). If this is what you want a .188' free bore with a one and a half degree throat angle should be good. My .175' free bore is good too.

The real question is how close to the drawing will the final reamer be,i.e. there are +/- tolerances on most reamer drawings and in the making of reamers and that makes a difference too). You can buy the identical reamer from the same maker and there will normally be some variations reamer to reamer. Most people have a view that everything is going to be 'dead on' to the proposed numbers on the drtawing when that is not always true and they also forget about the tolerances section of the reamer drawings. Like I said, there's some 'fudge factor' in all of this.

Robert Whitley
 
Robert,

'You're getting a little complicated in your discussion there. The bullet will make contact with the lands somewhere in the taper of the throat, wherever it does, based on the configuration of the front end of the bullet and your chamber,and the same bulllets can and do vary lot to lot, etc. so there is always some 'fudge factor' in all of this).'

I don't mean to get complicated, but you did answer my question. I understand about the different bullet configurations, dimensions varyng from lot to lot, etc. I am not really concerned with the variance......just wanted to confirm the 188 freebore while understanding the theoretical dimensions.

'What I understand you are communicating is you don't want the bearing surface of the bullet back in the case, but presumably not far up in the neck either,i.e. best is typically just ahead of the neck/shoulder junction). If this is what you want a .188' free bore with a one and a half degree throat angle should be good. My .175' free bore is good too.'

Yes...that was what I was trying to communicate. Yes...you have described where I want the bullet positioned in the case. And I understand that .175 will work as well as .188 considering the differences in bullets, reamer tolerances, etc.

'The real question is how close to the drawing will the final reamer be,i.e. there are +/- tolerances on most reamer drawings and in the making of reamers and that makes a difference too). You can buy the identical reamer from the same maker and there will normally be some variations reamer to reamer. Most people have a view that everything is going to be 'dead on' to the proposed numbers on the drtawing when that is not always true and they also forget about the tolerances section of the reamer drawings. Like I said, there's some 'fudge factor' in all of this.'

Yep....I savvy this. Thanks for taking the time to help me understand this reamer business.
 
I tried to order a 6.5-284 reamer this morning but Dave is out of town until the 29th so I was not able to. I am leaving the country until June 2nd so I will have to wait until then to get mine ordered.

I do not like either of the necks offered. I want a .298 or 299 neck. I also don't like the .125 radius at the neck/shoulder juncture but to me, this is less critical than the neck.

I guess I wait!
 

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