Tight bore barrels

[allen529]

What if any benefit or detractors are tight bore barrels? Boots Obermeyer used them frequently. I just found out my 6.5 barrel measures .254 not .256 which put a slight delay in chambering so the bushings can be ordered. I should have guessed. My 308 barrel (Obermeyer) measures .298.

 

[L.Sherm]

That's pretty snug.

 

[Cigarcop]

It’s def tighter than I’d want especially with some of today’s fat bullets...... he sells plenty of them though but it wouldn’t be my choice.

 

[DaveTooley]

No advantage at all to tight bores. If anything that's going the wrong direction.

 

[Liven The Dream]

The Tight Bore .308 Barrels Made by Many in years past where for Palma Shooters.

If one as to go or lived in England to to Shot Bisley Palma Matches The issued Ammo was Military 147 that was under sized.
This is no longer the case.

There is a good Warning about Tight Bore Barrels on Kriegers Barrels sight.
Bottom line not for Heavy Bullets do to High Pressure

Good Luck

 

[Larryh128]

What my limited experience has found with a tight bore is this, SUPER accurate barrel BUT you can't push it anywhere near as hard as a normal bore. I had 2 barrels that I chambered in 300 WSM, both are accurate BUT the tight bore required a charge of 2 grains less not to have pressure signs. With that said, it was a SUPER accurate barrel but I sold it because I wasn't going to load 2 different charges for the same caliber. It shot bug holes.

 

[RGRobinett]

What my limited experience has found with a tight bore is this, SUPER accurate barrel BUT you can't push it anywhere near as hard as a normal bore. I had 2 barrels that I chambered in 300 WSM, both are accurate BUT the tight bore required a charge of 2 grains less not to have pressure signs. With that said, it was a SUPER accurate barrel but I sold it because I wasn't going to load 2 different charges for the same caliber. It shot bug holes.

Empirical evidence strongly suggests that bullet failures - especially with long/heavy for caliber bullets - are more likely with 'tight' bore barrels. See Don's post above. RG

 

[scubohuntr]

That's why my tight Krieger Palma barrel is a 14 twist- no temptation to try shooting heavy bullets.

 

[Kurz]

While cleaning out the barrel rack on one occasion, I found a certain manufacturer's barrel inscribed with .298 x .3075. Turns out it was just another experiment looking for the ultimate combination of dimensions in order to achieve some perceived advantage. Mostly these tight barrels were used for the Palma shooters who were originally stuck with undersize bullets as noted above.

The 'normal' we used to use was .299 x .308 -5R which worked well in nearly every combination of bullet and case. We switched to .300 x .308 with the gas guns which is a good decision due to pressure concerns. Rarely these days, if ever, have I run into a situation where a tight bore/groove showed any advantage.

 

[allen529]

While cleaning out the barrel rack on one occasion, I found a certain manufacturer's barrel inscribed with .298 x .3075. Turns out it was just another experiment looking for the ultimate combination of dimensions in order to achieve some perceived advantage. Mostly these tight barrels were used for the Palma shooters who were originally stuck with undersize bullets as noted above.

The 'normal' we used to use was .299 x .308 -5R which worked well in nearly every combination of bullet and case. We switched to .300 x .308 with the gas guns which is a good decision due to pressure concerns. Rarely these days, if ever, have I run into a situation where a tight bore/groove showed any advantage.

My 308 from Obermeyer measured .298x.308 which I understood was because of the undersized Palma bullets even tho it was a 10tw. (I know 155's shoot good too. Lol) it shoots everything I put into it less than an inch. Somethings quite abit less than an inch too! Ive tried several powders and bullets from custom to commercial 185 to 208 and it likes them all. I have right at 1300 rounds through it with mild to hot loads and I will be sad once it shoots out. It will be an end of an era so to speak. Boots aint making em anymore.

Anyway, now I have an extra 6.5 barrel .254x.256 that I just may make a 6.5 Grendel as the gas guns dont like high pressures either. Lol

Allen