reamer help

B

Bob Brushingham

Member
I got a gift certificate from JGS and thought it was time for a .269 PPC reamer. I now have a Henriksen reamer with a .262 neck and .020 free bore. I have to use a small base die to get rid of the click. Should I go with a bigger base or keep it the same. What free bore do you suggest for Bart's Ultra's and Boat tail's?

Any input would be appriciated.
Bob
 
I have done a lot of experimenting and finally settled in on the .4402 .200 up from the bolt face, that is a good figure as long as your reaming method does allow the reamer to cut dead on size. The trend for a while was to go to that .3390, but I think that is too tight.

I have found that a .045 freebore works with the Barts Boat Tail and Ultra. The Boat Tail actually seats in further , but the flat base of the Ultra allows for the same amount of bullet making contact in the neck...........jackie
 
jackie schmidt said:
I have found that a .045 freebore works with the Barts Boat Tail and Ultra. The Boat Tail actually seats in further , but the flat base of the Ultra allows for the same amount of bullet making contact in the neck...........jackie
Click to expand...

May not be worth mentioning, but remember that freebore length is (probably) for a 1.5-degree half cone angle. I use twice that -- .090 -- but also have a 2-degree half cone angle. This was for the old Fowlers, but seems to work with a few other bullets. Anyway, the point is freebore length & throat angle do interact.
 
Brush,
The sizing dies you have on hand will guide you in making the right reamer choice for you.Size some fired cases in your various dies and measure the results in regard to reduction of case diameter at the shoulder and at .200 up from the case head. You want to reduce fired case diameter just enough to allow for smooth operation of the bolt during extraction but not so much as to prematurely wear out the case.
Most "high end" gunsmiths have a reamer- die program that they recommend.Some have a minimalistic approach to sizing while others have a "size a little more than you need and stay on top of the brass" approach.I have tried both and find no difference in inherent accuracy one way or the other. The unsized portion of the neck( lower area) is responsible for case alignment in either program.
If you have one die that produces straighter cases than other dies that you have, I would size some cases in that die and send them off to the reamer mfg requesting that his reamer body dimensions are ground to work with that die. Leave the details up to them.
In regard to freebore a few things need to be considered. Case length of new lapua trimmed and turned brass rarely exceeds 1.500,fired cases are easy to maintain at 1.500.You dont want your case necks any closer than .010 to the end of the chamber so a 1.510 chamber length is about right. A freebore of .030--is probably best for bullets built on a .790 jacket,whereas a .050 is probably best for bullets built on an .825 jacket. A 1.510--.040 should work well for both.
Many hard core shooters have searched long and hard for the ultimate reamer bullet combo.I don't think any have definitively found it. Some guys like their bullets seated a little deeper in the case neck than others.As long as your chosen bullet can engage the rifling and remain in the upper two thirds of the case neck , while retaining a solid grip on the bullet shank you are within an acceptable freebore range.
The .269 nk. intrigues me as well. I don't know how the neck bushing- neck tension formula will play out with heavier neck thickness. Perhaps someone in "the know" can comment on that.
Joel
 
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Joel, the Barts Boat Tail built on the .790 jacket actually goes .055 further into the case than a Barts Ultra built on a .825 Jacket. With todays bullets, It's more times than not the ogive, not the jacket length, that determines what free bore you should use..........jackie
 
When Billy Stevens built my 6PPC we used his reamer design with a .045" freebore and a 1 degree - 30 [1.5 degree] throat angle. The base dimension is .4401, .200 up from the bolt face. When I asked him which of Bart's flat base bullets he would recommend, he suggested the Ultra. That's what I use today.
 
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Jackie,
Yes you are correct. It's difficult to cover all the bases in such a brief format. My generalized example was for a flat base 7-3/4 ogive bullet in either .790 or .825. Higher ogive bullets,boattails and bullets with less bearing surface would be better served by a shorter freebore. A 1.510-- .040 reamer should still accomodate most bullets available today.
I am curious as to the chamber length of Bob's . 020 fb reamer as that length fits into the equation as well. In general terms, a common bullet seated at jam in 1.500 brass will be the same overall length in a 1.510--.050fb chamber as it will be in a 1.525--.035fb chamber.Where freebore diameter is usually .2435-ish, excess chamber length diameter is the same as the case neck + .002 or so, this could be .269 in our chamber.. All this space does nothing to support a bullet as it enters the rifling.So most BR shooters opt for minimum chamber length and adequate freebore length to accomodate their chosen bullet.
If Bob's current reamer is a 1.510--.020fb it is very short indeed and would gag on a 68gr.7-3/4 .825 flatbase,but it would probably love a .790 jacket 65gr 8-1/2 ogive flatbase or a sleek little boattail.
The vaunted JGS 1045 reamer of fame was( and is) a 1.525--.060 design.A sleek, short jacket boattail would be challenged to touch the rifling in this chamber.
Of course most of you guys know this stuff already, I only mention it for the newbies out there.
Joel
 
The Henriksen reamer print says 1.50 chamber length but I have put a 1.510 case in and closed the bolt with ni problem. How long it is I don't know I don't have any case which is longer.
 
Brush,
Your Henrickson reamer should have the OAL as well as other pertinent info laser etched into its shank. If Donny has it he can tell you what's printed on there. In any case if your reamer print says it's a 1.500 chamber length you gotta believe it for now and keep your brass at 1.490 or less. We would like to keep you around for a few more years at least ( IBS needs the money and the Genesee boys would be lost without you).What sizing dies do you have ?
Joel
 
redding fls Die, redding small base fls die and a Hornaday FL die( no bushings) which sizes like a .257 button. That would be no good for the .269 chamber.
 
I seem to be living in column B this morning, so here is a notion from it.

For all my long-range benchrest chambering reamers, I now specify the throat for the shortest bullet I'm apt to use. Now the bigger cases of long-range BR aren't the same animal, I know. Still, the accuracy levels required to win are the same. Or so I claim.

As far as bearing surface goes, we're sometimes talking differences of .1 here -- the difference between a 155 Palma and a 187 BIBs (or 240 Sierra). Compromise on freebore length really isn't an option. (Obviously, different twist barrels are needed to shoot these bullets, but I can use the same chambering.)

This because some of my earlier reamers were set up for *exactly* one bullet, and twice it turned out to be the one needing the greatest freebore length, so I got locked into that bullet.

The answer for me turned out to be specifying the freebore length for the shortest bullet, then using a throating reamer whenever a barrel was set up for a longer bullet.

I know that in theory, two operations, two tools, aren't as precise. Hasn't worked out that way. And you could argue, given tooling and techniques, that any .0001 misalignment is transferred from the leade to the neck or shoulder -- a better place for it, I think

I haven't done this for a PPC. I have for a .30 BR, where my reamer has zero freebore lenght. The number of X's didn't drop (sadly, it didn't go up, either). If I ever get another PPC reamer, I think that's what I'll do.

Anybody tried this with a PPC?
 
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