Barrel length for 6.5 Creedmoor, bolt gun or AR...

[Cross]

Gents, I've got a question for the collective here. I'm modestly invested in 6.5 Creedmoor and I'm a believer in what the round can do. I've currently got a gas gun with a 20" barrel and a bolt gun with a 24" barrel on it, both shoot very well and both handle extremely well- I've got zero complaints whatsoever. I've got two additional guns to build on the horizon- one each semi and bolt action. I'm interested in what the thoughts are on barrel length for that caliber in gas or bolt guns. My bolt gun is pushing 140gr at 2806 and the gas gun is pushing the same round at 2620. While those velocities aren't bad, the gas gun in particular does start to run out of steam at extended ranges. To me, it seems that in order to take advantage of the high BC projectile, velocity is more or less critical. For a 308, I don't mind a 16-20" barrel, but since these guns are purely long range, F Class, and grasslands play guns, I'm leaning toward running 24-26 inch barrels on the rifles I'm putting together soon. Handling and ease of transport isn't huge on the priority list as these might see limited use in PRS matches, but will primarily be moved from the truck to the firing line and back.

Ignoring the extra length and weight and subsequent penalty on handling and packability, what would you consider an ideal length for a Creedmoor barrel? Can anyone with some similar rifles of varying lengths fill me in on MV disparity? I'm extremely familiar with the negligible practical difference on barrel length for 308's, but I'm still learning with the 6.5 and don't have any real data compiled. If a 26" barrel is worth 100-120FPS, I'm willing to deal with the weight and length for the better long range performance. The round seems to be at its best when it's moving pretty fast, but I'm open to feedback from folks who've been using it, .260, and similar calibers for longer than I have.

 

[Chris Taylor]

If this is gonna be a pretty strictly play gun, no reason not to go longer on a bolt gun. Ok, there are reasons, but not major.

 

[MattJames]

It seems weirdly enough that the 22 inch barrels tend to be fairly common for the 6.5 CM and shoot quite well. But commonly you will find 22-26 inch guns, if I had to do it over again I would have liked to go for the 24. 26 gets a bit long for someone of my height to tote around. I should have some MV data for you out of the 26 inch in April some time.

Question- Are you rolling your own or shooting factory 140 AMAX stuff?

 

[Cross]

I've got a pile of factory loaded AMAX that I've been working through in order to generate brass. My assumption is that I can milk a little more MV from the longer barrel once I start working up a load for the gun, when it's built. That's why I'm interested in seeing numbers- if at the end of the day I can lose 4" of barrel for a 1/2 mil of wind at distance, it's an easy choice. If it's not quite so obvious, it'll be a somewhat trickier question to answer. Right now my comparable data is between a gasser and a bolt gun, so the numbers aren't all that useful..

 

[Gedro]

I am on my second 6.5 creedmoor barrel. My first was a 26" Brux and I ran Berger 140 VLD's out of it at 2830 fps with Reloader 17

My current barrel is a 30" Bartlein and I am running Berger 140 hybrids out of it at 2950 fps with H4350.
I use HBN coated bullets in both barrels
The 30" barrel is on my dedicated F class rifle. It is a barrel blank and is too heavy to pack around but the extra length definitely got me more velocity.

 

[MattJames]

2950 seems a bit low for a 30 inch barrel.

 

[tylerw02]

2950 seems a bit low for a 30 inch barrel.

That seems about all the 6.5 creed has in it from my experience.


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[Gedro]

I was able to get 3035 fps out of the 30" barrel with Reloader 17 but that was around max pressure and decided to run with the H4350 instead.

 

[MattJames]

Is the softer hornady brass also a consideration with potential MV?

 

[tylerw02]

From owning a plethora of 6.5 cartridges, seems the thing that matters on MV is how much pressure the case tolerates, the firing pin of the gun, and the case design itself. The 6.5x47 ha a small primer and seems to tolerate pressure well, though it will not produce the speeds of a 6.5 creed or .260 Rem.

On my AI the biggest issue was cratering and piercing primers. I've heard of a few 700s having the issue too. Most custom actions don't seem to have it. I adjusted my firing pin and my issues went away. Though chasing speed isn't the most important thing...just hitting the accuracy node at an acceptable speed and choosing the right bullet is more important than chrono numbers.


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[Gedro]

I run Hornady and Nosler brass both. I have 10 firings on some of my Hornady brass. Annealing them both after every firing and I FL size bumping the shoulders .001". When I tested the two brass against each other with the same powder charge, there was indeed a difference in MV. After testing the volume of the cases with water, I found that there was a volume difference. I can not say as far as the softness of the brass goes however. Here are my results on MV between the two.

 

[tylerw02]

That seems really fast for a 6.5 creed with 140s. That's 6.5-284 speed. Verify/true your velocity with field data? Chronos are often wrong. Mine is about 35 FPS slower than field data. I shoot a .260 with 43.5 gr of 4350 and I'm getting 2850 according to my field data.

On the speed difference, because the cases are different dimensionally, you'd expect different pressure, velocity, and accuracy with the same charge weight.


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[Gedro]

Yes it is fast for a creed. I am running a 30" barrel and HBN coated bullets. Verified out to a mile if that matters. I also have tested my magneto speed against a Oehler 35p and a Steinert acoustic as well. The magneto speed and the 35p run within 5% of each other within a 40 shot string. But, That is another thread topic.

 

[tylerw02]

I'm impressed! That's the fastest I've heard of a Creed running.


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[Gedro]

I am a speed demon

 

[MattJames]

Huh, well sounds like Hornady fixed some of the issues with soft brass, as that seems to be the chief complaint.

Gedro- Whats your impressions of the Nosler brass? Is it worth the extra $ if it reduces the time spent annealing? It seems component wise 260 REM gets the nod to being superior simply by virtue of the Lapua brass. But that brings its own cost considerations along with it.

I was considering running the 130 VLD as a 1000k and under cartridge. It gives up a lot past 1k to the 140 but its a toss up between better PBR (really comes down to target size being the consideration there) and bucking wind with the 140's.

One of these days, when I have the time I am going to get myself reloading. I need to have someone walk me through the process hands on before I'd feel comfy doing it on my own.

 

[tylerw02]

Shooting two loads is silly. The 130 doesn't really give you much of anything. Also, I would skip the VLD altogether and start with the 140 Hybrid.


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[MattJames]

Well as long as I'm rocking factory or semi-factory (Copp Creek) ammo, the bullet is about all I have to experiment with.

 

[tylerw02]

Ahhhh. I would just shoot factory Hornady in that case or start handloading. You'll save so much cash over the years and you'll be able to tune the load to your barrel.


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[MattJames]

Thats the route I'm going to take for now, with the goal of getting a 140 Hybrid Load developed once i get a good setup dialed in. I have a book understand of the reloading process, but until I put hands on and go through the process, see the cause and effect, hopefully not fuck up; its all academic until that happens.