6.5X284 freebore question

[dbramley]

I have an old reamer throated for 142gr SMK at .180. Dave Kiff recommended .175 for 140gr berger hybrids. I tried to measure it out last night but came up with a number much longer than this. .175 just seems short to me but looking for opinions and or suggested freebore for 140gr hybrids.

Lapua brass 6.5X284
Berger 140gr hybrids

I would like to stay ahead of doughnut area and expect + or - .020 jump

Thanks in advance.

 

[Rust]

What I've been doing is making up dummy rounds using the brass and bullets I intend to use, and sending several to Dave at PTG. He can then grind a reamer to match. Worked out well for .308 and .223. Been a few years for my 6.5 X 284 and don't know what I did with the print since I moved. Anyhow, I seated the bullets about as far out as practical while still maintaining enough for good grip by the neck. Left a bit more usable volume in the case BUT requires very careful load developement.

You can spec neck clearance for the brass you use, with Lapua I spec'd fairly tight for a no turn neck using Lapua brass for all three chamberings. I don't use anything but Lapua, learned that lesson years ago.

Hope this all makes sense to you.

You can also spec freebore diameter and leade angle, although 1-1/2 degrees is pretty much the best way to go.

Though it is more expensive, a bushed reamer is the way to go with the matching bushings. It is more expensive to go that route but it insures the straightest chamber.

 

[ShootDots]

I have an old reamer throated for 142gr SMK at .180. Dave Kiff recommended .175 for 140gr berger hybrids. I tried to measure it out last night but came up with a number much longer than this. .175 just seems short to me but looking for opinions and or suggested freebore for 140gr hybrids.

Lapua brass 6.5X284
Berger 140gr hybrids

I would like to stay ahead of doughnut area and expect + or - .020 jump

Thanks in advance.

You will be fine with a .175... I just did a .260A.I. and I am shooting the Berger 140 LRBT's which is a L-O-N-G bullet. I am out of the neck/ shoulder junction with a .168 freebore..

 

[dbramley]

Thanks for the replies, sounds like I will be able to use the reamer I have. I made up a dummy round and tried to measure it and compare to other, older chamber but came up with a measurement (likely wrong) of like .220 to give me .030 to clear doughnut and .020 to jump. I will chamber it and throat it with uni-throater if needed.

Thanks again

 

[Patch700]

Thanks for the replies, sounds like I will be able to use the reamer I have. I made up a dummy round and tried to measure it and compare to other, older chamber but came up with a measurement (likely wrong) of like .220 to give me .030 to clear doughnut and .020 to jump. I will chamber it and throat it with uni-throater if needed.

Thanks again

It is very possible that your rough measurement of the round that came out of the original chamber (specd. 180") is actually indeed now .220" if there were any number of rounds fired down that barrel causing throat erosion.

I think you'll find that .170"-.180" will work nicely for your scenario.

 

[dbramley]

Thanks for the replies, sounds like I will be able to use the reamer I have. I made up a dummy round and tried to measure it and compare to other, older chamber but came up with a measurement (likely wrong) of like .220 to give me .030 to clear doughnut and .020 to jump. I will chamber it and throat it with uni-throater if needed.

Thanks again

It is very possible that your rough measurement of the round that came out of the original chamber (specd. 180") is actually indeed now .220" if there were any number of rounds fired down that barrel causing throat erosion.

I think you'll find that .170"-.180" will work nicely for your scenario.

That's good news, thanks for your input.

 

[10XSHOOTER]

My 6.5 X .284 PTG reamer has .297 neck dia for Lapua brass, no turn. .180 freebore for 142 MK. Loaded rounds .294 dia.

 

[dbramley]

Thank you, I am happy to hear that as my reamer has .188 FB

 

[Badbob]

I am also looking for advice on a 6.5x284 reamer. I want to work with Berger 140s-hunting.

I have a Stiller Predator MEDIUM action that gives me some more flexibility. The mag well is 3.2" I do want to turn my necks so I'm thinking .296".

Any ideas on the freebore distance? Or even better yet, share your reamer drawing.

Many thanks! BB