barrel dimensions

[Mhall]

Is there any benifit to ordering a barrel with a smaller bore. Say a .337 instead of a .338. I see barrel makers offer a few choices. Is there a reason and is it benifical. Thanks

 

[zullo74]

Is there any benefit to ordering a barrel with a smaller bore. Say a .337 instead of a .338. I see barrel makers offer a few choices. Is there a reason and is it beneficial. Thanks

A tight bore develops more pressure with less powder. Less powder equates to less throat erosion. Less throat erosion leads to longer barrel life. You do the math!

 

[TRECustom]

What little experience I have had makes me think that Lilja barrels are slightly tighter than most. You have to be very careful with reamer pilot bushing diameters. Some standard reamer pilots are too tight or won't go into a Lilja barrel. It must be by design. I would call Dan Lilja and ask him what the advantage is. What I have seen is that velocities are measurably higher than with the other custom barrels I know anything about.

Just my opinion based on limited experience.

Tom

 

[blawton]

Frank,

this completely depends on what bullets your are going to shoot and what the barrel length is going to be. You have to be careful about how you set them up because overpressure will be a big problem if you dont.

 

[DS]

notaguru

explain more please?

 

[blawton]

The 338 caliber does not really have any smaller bullets most hang real close to 338 in the first place some even 339. So the tighter the bore the more pressure you will build. Unless you want to run a 20" barrel or less a standard bore will be your best choice. The only real reason to run the bore tight is to still get good burn with the slower powders instead of having to switch to faster powder witch in turn effects the high end of your MV's. Your best off to run the longer barrels and slower powder and get the extra mv's in a caliber like this unless your doing a whisper or shorter range tac gun. Using tight barrels in this case can cause unwanted overpressure problems when using fatter bullets then normal. There is a # on our website if you like to give me a call and i may be able to help you further.

 

[butchlambert]

I've seen different velocities from different barrels and it doesn't always coincide with bore size. .001 tighter in bore size will probably not show a lot of pressure difference. If you shoot a lot over a chrono, you will understand what I am saying. They ain't no absolutes in this.
Butch

 

[Rustystud]

I think some of these post deserve a "golden shevel" award to remove the BS.

A tight bore example:

308 Winchester

When shooting long range, IE: Palma that is limited to 155 grain bullets which have a shorter bearing surface. Most of the Palma shooters shoot 1:12 to 1: 14 twist barrels with a .298 " tight bore"

308 Winchester at long range, IE: F-TR that is not limited to any bullet weight. Many F-TR shooters shoot 185-210 grain bullets for their better BC. They generally shoot .3000 bores with a 1:10 to 1:12 twist barrel.

Bullet length, barrel twist, and barrel length all have a relationship. They go along with barrel life in which heat and pressure are the enemy. There is an optimal relationship between bullet length and bore diameter.

Nat Lambeth

 

[spclark]

Some brands of bullets differ dimensionally from similar products from other manufacturers.

As an example only, .30 & .6mm Lapua Scenars tend to be very slightly smaller than, say Berger or Sierra. A smaller bore diameter helps the Lapua (in this case) work to best advantage, where a Berger or Sierra bullet may reach over-pressure conditions with the load for the Lapua.

What Nat suggested for shooting Palma is another circumstance where a tighter bore may help a shooter using a given bullet achieve a velocity that otherwise would be unobtainable with a safe load.

Bottom line: it's nice to have an option, as long as you know what it can do for you. Otherwise it just confuses things.

 

[blawton]

Barrel life in this case is not gonna change much if you go with a tighter bore and load less powder. The difference is going to be so small. There are much better ways to extend barrel life 2-3x without having to sacrifice your upper end of the MV's. What you need to do is figure out what bullets your shooting and which bullets you would like to try as well and then its much easier to tell what needs done. If you are indeed doing a 338, stick with a standard setup and you will be very happy with the results.

 

[sailhertoo]

I think some of these post deserve a "golden shevel" award to remove the BS.

A tight bore example:

308 Winchester

When shooting long range, IE: Palma that is limited to 155 grain bullets which have a shorter bearing surface. Most of the Palma shooters shoot 1:12 to 1: 14 twist barrels with a .298 " tight bore"

308 Winchester at long range, IE: F-TR that is not limited to any bullet weight. Many F-TR shooters shoot 185-210 grain bullets for their better BC. They generally shoot .3000 bores with a 1:10 to 1:12 twist barrel.

Bullet length, barrel twist, and barrel length all have a relationship. They go along with barrel life in which heat and pressure are the enemy. There is an optimal relationship between bullet length and bore diameter.

Nat Lambeth

Ha Ha......

Per'spective..