6.5CM Proof Research group expansion

[bigjake83]

Recently put together a 6.5 Creedmoor on a SP10 chassis using a 24" Proof Research Carbon Wrapped Barrel. Took it out to a 100 yard indoor range today I was going to shoot a 5x5 to see what the accuracy average was but it just wasn't the day to conduct I test like that, just to many people doing stupid shit and the firing line is one long table and we had to stop a few times because people we're just shaking the table too much or shooting 50 BMGs.

Instead @FALex and myself wanted to see how the carbon fiber wrapped barrel behaved compared to heavy profile stainless steel barrels. To this point the Proof Barrel has been consistently shooting Hornady 147's around 1/2 MOA or less, so I did a 15rd Mag Dump and then we each shot a 5rd group for accuracy and they both opened up just over MOA.

Has anyone else here done a test like this ? I'm curious if this is the norm or if carbon fiber wrapped barrels behave differently than solid stainless steel??

3 bottom 5rd groups were slow fired then we let the barrel cool for about 10 mins, did a 15rd mag Dump then we shot the two top 5rd groups with the hot barrel.

 

[Sogan]

What results doing the same test with a heavy profile stainless steel barrel do you get?

 

[bigjake83]

What results doing the same test with a heavy profile stainless steel barrel do you get?

I haven't, I usually shoot using a one minute cadence, so I'll shoot one round every 60 seconds and take a break in between groups when I'm trying to do a 5x5.

I know all barrels open up when they get hot but I have no point of reference to compare this to. When I get home I am going to do the same test to my .308 with a heavy profile Bartlein.

I did borescope the barrel when I got home today and I was actually surprised how minimal the copper fouling was since I haven't cleaned this Barrel since I got it and I'm about 75rds in right now

 

[Earnhardt]

I have also observed this. With multiple Proof carbon barrels. I bought an AI AT prefit in 308 and this occurred much worse than you show. I sent it back and got a new one. It still does it but to a much smaller degree. My identical to your barrel does is as well.

At first I thought it was a bad barrel. @lowlight says it's just mirage coming off the barrel. So I thought maybe that's it. I've stated before to people on this forum that Proof Carbon barrels probably aren't the best choice for high volume rifles. Because of this idea. Then I started suspecting that it's a thermal issue with barrel rigidity. Seeing yours adds another data point for me. Heat definitely affects these barrels much more than steel.

Yup…nailed it on the head

I’ve got 3 Carbon fiber barrels now. A 24” Chr Arms 6.5 CM barrel, a 24” BSF 6.5 CM barrel, and a newly purchased 24” Proof 6.5 CM barrel…and they’re all the same, once they get heat in them, the groups start to open up

I also have 2 steel barrels. A 22” Ballistic Adv. 6.5 CM barrel (heavy as hell), and a 22” Rainier ultra match 6.5 CM barrel
The groups do not open up on the steel barrels at all like the carbon fiber barrels do, when they get warm
(And sorry fellas, the 79oz. 22” Ballistic Advantage barrel is the most accurate. Hot or cold…)

 

[roberthu526]

Tagging along. I thought a big advantage of carbon fiber barrel is very little impact from heat? Or am I thinking the opposite?

 

[TonyTheTiger]

I personally know a guy that uses (used? Haven't talked to him in a while..) a Proof carbon for 3 gun. If a stage requires more than 40-50 rounds he's screwed, once it's hot bullets blow apart leaving the muzzle. Sample of one, but very disconcerting nonetheless.

 

[bobke]

I have only one 6.5CM CF AR barrel to draw experience from, and will pay more attention to shift. Have you all with small frame CF barrels noticed same shift in 223/6ARC/6.5GR, or is limited or more specific to large frame barrels?

 

[NGCSUGrad09]

Shoot the full steel and report back for a fair comparison.

Generally speaking, they should behave similarly...meaning when they get hot they'll open up but so do steel barrels. The difference is a full steel may take a little longer to heat up. They also take longer to cool down and at the heavier weight. Shot cadence, how overbore a cartridge is, ambient temps, etc all affect how fast something will heat up. The action or receiver design it is mounted to can also create some variances.

As for my experiences, I've shot 20+ round extended stages with a 6CM carbon barrel in 2-3 minutes and maintained hitting competitive targets. Ive also shot 30-40 shot rifle strings with a carbon barreled 556 AR in action carbine, 2-gun and 3-gun events and had similar performance results to nearly identical setup guns with steel barrels.

They are still steel barrels, just a lightweight profile one with the carbon wrapping around it.
Carbon wrapped barrels aren't for every application, but they have their place when you need to save some weight.

 

[deersniper]

usually shoot using a one minute cadence, so I'll shoot one round every 60 seconds

Man you have patience for days

 

[Supersubes]

Man you have patience for days

Exactly what I was thinking.

 

[bigjake83]

Man you have patience for days

Yeah but my groupings reflect the payoff.

Update on the Proof Research 6.5 CM.

(1) Does NOT like a clean barrel! Last time I did a squeaky clean Barrel scrub down it took 15rds to get the barrel to start grouping consistently at 1/2 MOA again, in short she likes to be a dirty bitch witch I honestly like better for my laziness.

(2) I have not had a chance to reshoot that last Hight Temp Drill of a 15rd Mag Dump then to slow controlled 5rd group. So I can remove mirage as a possibly contributing factor for the groups opening up I will use a F-Class style barrel shield with a added layer or thremo Tape.

Once a get a chance to repeat it that test I'll update this thread.

Side note I have SS heavy profile Bartlein coming in next week so ill have a solid SS to compare to as well.

 

[bobke]

Jake
A question about your shooting sequence. When you’re allowing a minute between shots, are you feeding from mag and allowing rounds to sit in ever warming chamber, or single feeding an empty chamber. Just wondering if chamber temps are having an effect on group size. Know that’s getting down a rabbit hole, but curious nonetheless.

 

[bigjake83]

Jake
A question about your shooting sequence. When you’re allowing a minute between shots, are you feeding from mag and allowing rounds to sit in ever warming chamber, or single feeding an empty chamber. Just wondering if chamber temps are having an effect on group size. Know that’s getting down a rabbit hole, but curious nonetheless.

Load 5rd in a Pmag, chamber fire and allow for up to 60 sec per shot. I do a very slow and controlled trigger squeeze wait for the perfect moment/heartbeat/ breath to break the shot, drive the recoil until it comes to rest after the rifle's multiple recoil impulses... reset trigger...check my rifles cant..run threw a check list in my mind, am I relaxed? Is my grip the same....... Doing all this usually results in a 60 sec shot cadence.

I'll run up (3) 5rd mags at that cadence but after the 15th round / 3rd group ill allow the barrel to cool for 10 mins before I rise and repeat.

This is how I conduct my 6x5 testing.