280AI freebore

[ormandj]

I’m pivoting and going with a 280AI on a long action w/ a 20” 8.5 twist Bartlein barrel (shoot only suppressed). I’m assuming the SAAMI reamer is the way to go now, but is the standard specified freebore (well, in this cartridge, I guess the tapered lead, since there doesn’t look to be much freebore at all) appropriate for 180 Hybrid Targets, or would you suggest deviating?

I tried searching and only found a few references, but wanted to see what the current “best practice” was for this cartridge with 180 Hybrids. I do have CIP magazine length (3.750”) COAL to utilize. I would prefer to have some margin of error to chase the lands as the barrel wears, but also want to keep the bearing surface out of the neck shoulder junction, perhaps 0.01-0.03” off. I’m completely open to feedback and suggestions!

 

[tac284]

When I had JGS make my reamer I sent in a dummy round with a Berger 168 HVLD seated at the neck/shoulder jct. and they measured it at .075 freebore. Can’t remember how this compared to SAMMI…

 

[SKWERLZ]

I think Saami is .180
I’d say anything between the saum freebore (.090) and Saami should work well

 

[NZ_Fclass]

MIne has 100thou

 

[jkohler]

My current reamer from JGS has .124 freebore. Works well with 168 Berger hunting VLD’s and also Nosler 168 accubond Lr.

 

[ormandj]

Definitely looking for info with the 180 Hybrids. Thank you folks!

 

[kev77]

Definitely looking for info with the 180 Hybrids. Thank you folks!

.160 is perfect for the 180hyb. That's what I ran I. Fclass

 

[ormandj]

.160 is perfect for the 180hyb. That's what I ran I. Fclass

Awesome, thank you for the information. Still shooting 280AI?

 

[kev77]

Awesome, thank you for the information. Still shooting 280AI?

At times, only because I have a shit tonne of components it.

 

[ormandj]

At times, only because I have a shit tonne of components it.

What’d you end up moving on to?

 

[kev77]

What’d you end up moving on to?

300 saum imp. Shooting 208s at 2930fps for fclass. 300max actually and .215fb

 

[Nubs]

Reviving an old-ish thread.

My Manson reamer was delivered last week and I was trying to calculate freebore from their reamer markup. Needless to say, I couldn't figure it out, so I sent them an email. The email from Manson stated that there is no freebore on this specific chamber, and that the lead angle starts immediately after the neck diameter. This makes sense, based on my inability to calculate a freebore dimension from the drawing.

So, have any of you guys used a Manson .280AI reamer, and are you throat reaming separately to run heavier projos?

 

[ormandj]

Reviving an old-ish thread.

My Manson reamer was delivered last week and I was trying to calculate freebore from their reamer markup. Needless to say, I couldn't figure it out, so I sent them an email. The email from Manson stated that there is no freebore on this specific chamber, and that the lead angle starts immediately after the neck diameter. This makes sense, based on my inability to calculate a freebore dimension from the drawing.

So, have any of you guys used a Manson .280AI reamer, and are you throat reaming separately to run heavier projos?

This is the unfortunate aspect of this cartridge; nobody seems willing to share info. I finally have some brass and bullets, and will probably do some CAD work too. Let me know if you get any info in the meantime; the tool makers should have the real skinny on these and it’s surprising to me they aren’t spilling the beans.

 

[Beiruty]

Read here:

How Much Does It Matter? Overall Summary

As long-range shooters, we tend to obsess over every little detail. After all, we’re trying to hit r...

precisionrifleblog.com

 

[UCO___]

.160 is perfect for the 180hyb. That's what I ran I. Fclass

Sorry to bring an old thread back to life, but I am in the process of buying a 280ai reamer and want to make sure I understand what I am looking at. On the SAAMI spec, the end of the freebore, as I understand it, is 2.754" and the end of the case is 2.575" for a total freebore of 0.179". Help me get this right since the 180 hybrid is also my endgame.

Thanks in advance!

 

[kev77]

Sorry to bring an old thread back to life, but I am in the process of buying a 280ai reamer and want to make sure I understand what I am looking at. On the SAAMI spec, the end of the freebore, as I understand it, is 2.754" and the end of the case is 2.575" for a total freebore of 0.179". Help me get this right since the 180 hybrid is also my endgame.

Thanks in advance!

Yes that will work just fine

 

[bks22345]

I have a 280ai with a PT&G “match” chamber. 0.170 freebore. My COAL to touch is 3.640” with the 180 hybrids so they are long. Definitely a single load application in my setup.