Modify Reamer?
- Thread starter peterdobson
- Start date
Your figures don't make sense. .334 is smaller than .338... perhaps a typo? .341 ?
Careful stoning one edge and measuring and then the opposite edge and measuring and repeating all around is one method. Careful is important. The other is to remove the throat entirely and use a separate throater.
Guntech and others, Obermeyer was one of the earlier match reamer designers that we know of and he did .3085" for .308 Win.
As mentioned, almost all match reamers are .0005" over bullet diameter and the BR guys have always stated that the leade specifications are the most important to accuracy. Have a minimum CIP 300 Norma which is .309".
Related to reamer issues, many with 6.5X47 Lapua have had issues where there has not been enough room for the neck to expand. We just ordered a JGS with .2994" neck(ammo is .290"). Also ordered a new spec 300 PRC reamer after being advised of issues by JGS:
"The "clicker" problem is what guys are calling it when the brass is expanding a bit larger than the chamber after several firings, and it's causing a clicking noise and sticking upon extraction. Alex Wheeler "fixed" the chambers by raising the base diameter by .002 which allows the SAAMI sizing dies to work properly again.
Here's some reading materials about the clicker problems on the PRCs
https://www.longrangehunting.com/threads/the-prc-die-problem.253223/
and here:
https://www.longrangeonly.com/forum/threads/6-5-prc-dies-not-sizing-enough.6782/post-79382
These mostly talk about the 6.5 but it's happening on all three of the PRC chambers."
As mentioned, almost all match reamers are .0005" over bullet diameter and the BR guys have always stated that the leade specifications are the most important to accuracy. Have a minimum CIP 300 Norma which is .309".
Related to reamer issues, many with 6.5X47 Lapua have had issues where there has not been enough room for the neck to expand. We just ordered a JGS with .2994" neck(ammo is .290"). Also ordered a new spec 300 PRC reamer after being advised of issues by JGS:
"The "clicker" problem is what guys are calling it when the brass is expanding a bit larger than the chamber after several firings, and it's causing a clicking noise and sticking upon extraction. Alex Wheeler "fixed" the chambers by raising the base diameter by .002 which allows the SAAMI sizing dies to work properly again.
Here's some reading materials about the clicker problems on the PRCs
https://www.longrangehunting.com/threads/the-prc-die-problem.253223/
and here:
https://www.longrangeonly.com/forum/threads/6-5-prc-dies-not-sizing-enough.6782/post-79382
These mostly talk about the 6.5 but it's happening on all three of the PRC chambers."
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I have stoned reamers to reduce dimensions and have a pretty good system for doing so. Nonetheless, my preference is to simply remove the throat and throat separately. One caveat is that one must use a spiral fluted reamer to throat a five groove barrel ( I dislike 5 groove barrels, by the way). Otherwise the reamer is deflected by the lands. A very close fitting pilot helps.
Have you tried it and seen how it shot, or are you just going by someone else's suggestion on what it should be? There is a bit of tolerance in reamer specs it might already be at what you think you need. If your reamer is running slightly under spec.
Yup, you get chatter marks if you don't use a spiral throater. I've had the same issue with six groove barrels as well.
I had difficulties with a Match grade Schilen, with six grooves
The grooves were very wide and the lands were very narrow. I used the barrel to make up an M1 Carbine barrel. I had to start over, after chattering the first chamber. The reamer was new, unused, from Gary Eakin.
Likely it was mor my fault
