Freebore length?

[daved20319]

Kind of in the weeds, maybe, but I'm planning on putting a new barrel on my 12 FV 6.5 Creedmoor, and at least one of the sources I'm looking at offers chambers with shorter than SAAMI spec freebore. I have this rifle set up as a single shot, so no issues with mag length, but is there any other reason I might benefit from a shorter freebore?

As the goal is long range shooting, I expect to mostly be using heavier bullets, with the 147 gr. ELD-M probably the heaviest. Have been testing some Berger 144 gr. LR Hybrids, but the results have been less than great. I switched this rifle from .223 to 6.5 CM with a take-off Savage barrel, it shoots well but is a copper mine, thus the search for something better. And just to be clear, this isn't a "what barrel should I get?" thread, I'm just curious about freebore options other than SAAMI spec. Thanks!

Dave

[celltech]

Since you are not constrained by mag length issues, and want to shoot the heavies, just stick with the .199 spec. If you were shooting nothing but sub 130gr bullets and wanted to keep them mag length then the shorter freebore might be useful.

[SageRat Shooter]

I built a .260 Remington a few years back and had it chambered in a "Match". That gave me a little more freebore than SAAMI spec. It allowed me to seat the 143 ELD-X way out to take advantage of the case capacity. Being that you're referencing the 147 ELD-M I'd say that you probably want more freebore than less. I bought a Criterion prefit barrel, but I can't remeber how much more freebore they said it had.

[Fuj']

I built a .260 Remington a few years back and had it chambered in a "Match". That gave me a little more freebore than SAAMI spec. It allowed me to seat the 143 ELD-X way out to take advantage of the case capacity. Being that you're referencing the 147 ELD-M I'd say that you probably want more freebore than less. I bought a Criterion prefit barrel, but I can't remeber how much more freebore they said it had.

My Criterion large shank Varmint had a .209 freebore, as verified
from a chamber cast I do on all my barrels. It's nothing special I
ordered. It's the way Criterion sent it to me. And yes it came
direct from Criterion from the early days when they were still in
the Kreiger shop. I no longer shoot the Creedmoor, but if I did,
I'd go with a 7.5 twist and a little longer freebore then SAMMI

[big honkin jeep]

I shoot a factory barreled Savage so this may be useful, maybe not. For my pet load I load with my bullets touching the lands by using a neck sizing die, loading a little long, and letting the lands finish seating the bullet. I've found it's hard to get more consistent than that and have been able to get some fantastic accuracy doing it. My 700s all seem to have come with longer freebore and I cant seem to replicate this with them and still feed from the mag. It seems to me just as a personal preference I prefer a shorter freebore so my bullets will reach the lands over a longer one.

[Robinhood]

Freebore is not the same as leade/throat.

[yobuck]

Freebore is not the same as leade/throat.
Maybe a technical description is needed in order to clear up some of our minds on the issue?

[Nor Cal Mikie]

Call it what you want, if you can't reach the lands from the start, what are you going to do after 75,100 or 150 rounds fired???
And you may be surprised at how fast the throat/lands move forward.
Go short. You can always go longer.
Go long and you'll need a re chamber to reach the lands.
Plan ahead.

[gbflyer]

Call it what you want, if you can't reach the lands from the start, what are you going to do after 75,100 or 150 rounds fired???
And you may be surprised at how fast the throat/lands move forward.
Go short. You can always go longer.
Go long and you'll need a re chamber to reach the lands.
Plan ahead.

I subscribe to that philosophy also. I had Manson build my 6.5 Creedmoor reamer with a .169 free bore. I can fit just about any bullet in a 2.8 mag, it will creep out longer all on its own.

Having said all that, the most consistent rifle in my collection has a chamber that I cannot get within .200 of the lands when loaded at magazine length. It just doesn’t care, the hole on the target just gets bigger. Lots of different barrel juju out there[emoji1]

[nksmfamjp]

Take the shortest bullet you will shoot. Seat the bullet so the bearing surface is just seated to the base of the neck. That is what you want roughly for oal of a round when bullet is touching the lands, unless you had a magazine to shorten that. You want your bullet seated to this position when it is touching the lands. In the end, you may jam it or seat as far back as 0.1” off, but normally I find 0.02-0.03” works pretty well. I won’t jam a hunting load.

Also, measure the OD of the loaded neck. Ideally, your chamber neck will be 0.001-0.005” bigger than your loaded round....if you won’t use the same brass and it’s neck thickness varies....like Win brass, you will want to start at plus 0.003”.

Find a gunsmith who is talking your language.....talk about your reloading plan, neck diameters and how you want freebore set to a loaded round sample. If that goes well, likely you will get what you want.

The warning signs are “you dont need that”, “I don’t have that”, “that’s not what the experts use”....guys that have what you want are saying I have these options, I’ve done this before, I can do that, what about this.... Of course, you should listen for sound logic and consider changing your plan, but...

[Robinhood]

Maybe a technical description is needed in order to clear up some of our minds on the issue?


I was hoping you could provide that. I just read it on a PTG print

[daved20319]

Thanks for all the responses, guys. Considering my application and use, I'm going to stick with SAAMI spec. Will likely be ordering a barrel today, later.

Dave