Selecting the right 6mm creedmoor barrel

[Ranger Bob]

My Tikka T3x donor rifle has come in and I'm ready to order a barrel. X-Caliber is having a sale so, given that they seem to get good reviews, I think I'm going to order from them. This will be my first 6creed so I'm looking for some advice on barrel selection. The range where I will do most of my shooting maxes out at 800yds. I'm in the Dallas area and there are certainly opportunities to shoot further distances but, those would be infrequent. I don't hunt but, I may join a "sniper league" at my local range this year.

The rifle is going in a KRG Bravo and I think I want the weight of a heavy palma profile. I would maybe go a little heavier but, probably not lighter. My big questions are what length, what twist and what rifling? I'm expecting to shoot 105's or 108's but, since I've never had a 6creed and don't know what the gun will like, I guess we'll see on that. I won't be running a suppressor but, I may occasionally run a brake.

My gut tells me to go with a 24", 7twist, 5R but, I am open to suggestions and advice.

Bob

 

[spife7980]

Your gut isn’t a bad choice.

 

[Ledzep]

5R is a good start. .237 land diameter (not .236 "tight bore"). I'd go 7.5" or 8" twist, personally. Anywhere from 22-26" is happy.

Why the slower twist?

3100*12/7*60= 318,000 rpm
3100*12/7.5*60= 297,000 rpm
3100*12/8*60= 279,000 rpm

If an 8 twist will stabilize the bullets you're shooting, it will drastically minimize the odds of blowing up a bullet as bore condition deteriorates. If an 8 twist won't stabilize your bullets (110-115gr), a 7.5 will and still reduces blow up risk.

Shoot a few 20-shot strings rapid fire in the summer with a dirty bore in a 7 twist and I'd be impressed if everything held together.

 

[Ranger Bob]

5R is a good start. .237 land diameter (not .236 "tight bore"). I'd go 7.5" or 8" twist, personally. Anywhere from 22-26" is happy.

Why the slower twist?

3100*12/7*60= 318,000 rpm
3100*12/7.5*60= 297,000 rpm
3100*12/8*60= 279,000 rpm

If an 8 twist will stabilize the bullets you're shooting, it will drastically minimize the odds of blowing up a bullet as bore condition deteriorates. If an 8 twist won't stabilize your bullets (110-115gr), a 7.5 will and still reduces blow up risk.

Shoot a few 20-shot strings rapid fire in the summer with a dirty bore in a 7 twist and I'd be impressed if everything held together.

The 5r is only available on a 7-twist. If I go with an 8-twist, the choices are 6 groove, 3r or 3 groove.

Bob

 

[MarinePMI]

3 grooves sure clean nicely ( have a pac-nor 3 groove, and it was a breeze to clean and shot well).

 

[Ranger Bob]

3 grooves sure clean nicely ( have a pac-nor 3 groove, and it was a breeze to clean and shot well).

I just don't know much about them. I've read a couple opinions about how they reduce deformation and thereby reduce pressure. Apparently they are popular for solid copper bullets which, I've never shot. Beyond this, I know nothing about them.

Bob

 

[MarinePMI]

Within the sub-caliber world (anything smaller than .224" bore) they have a strong following, exactly for what you mentioned; less deformation/jacket thickness sensitivity. Those tiny bullets amplify any type of anomaly in the core or jacket thickness. Since the jackets tend to be more sensitive, it was found (anecdotally) that for whatever reason, 3 grooves tended to show less issues (like the gray puff 50yds out as a bullet came apart). I have a .17AH with a pac-nor 3 groove as well (forgot about that until I started thinking about sub-caliber thing), and it shoots bug holes with 20gr HP's and some 1680.

During WWI, Springfields were made with two groove barrels, and they proved to be quite accurate. When you get right down to it, the grooves just ensure the bullet is spinning appropriately. In that regard, the number of them seems non-consequential (JMHO). Where the benefits lie (and are hotly debated at times) is fouling, barrel life and being more jacket friendly...

 

[Ranger Bob]

I contacted X-Caliber and asked about the 8twist with 5r and they got back to me right away and said they have it, leaving it off was an oversight and they will be adding it to the menu shortly. So...24", 5r, 8twist, heavy palma.

Bob

 

[Ranger Bob]

They updated the website quick! Barrel ordered.

Bob

 

[Gatorshark]

5r is a little slower too isnt it? I would love to see the range report when working up loads. I have an exact build planned.

Are you installing the barrel yourself?

 

[Ledzep]

Rifling type doesn't affect the twist rate, just the profile engraved into the bullet. 5R is a little easier on jackets than sharp square cut rifling.

 

[Ranger Bob]

5r is a little slower too isnt it? I would love to see the range report when working up loads. I have an exact build planned.

Are you installing the barrel yourself?

From what I've read, the 3r is a little faster than 5r and the 5r is a little faster than a traditional 6groove. I tend to stay in the tried and true camp rather than be an early adopter and there's just not much info out there on 3r for long range shooting.

I am going to install it myself. This will be my first prefit. I debated on whether to do a barrel nut style prefit or a shouldered and decided that I didn't want to take the risk of the shouldered prefit not gauging correctly. I found 6creed headspace gauges through Midway USA but, they were expensive (PTG). Hope I like 6creed with that investment. Now, I wait...lead time is 10-12 weeks.

Bob

 

[kthomas]

No comments on the barrel as I don't have a 6 creedmoor nor an X-caliber barrel.

However, your rifle will probably a bit front heavy with a 24-26" heavy Palma in a KRG Bravo chassis. My wife's 24" heavy Palma barrel was. We put two weighted metal KRG LOP spacers and that balanced it out nicely.

Just something to consider.