6br and powder fouling?

[LRPV]

I have 175 rounds down a new SS 6br 8 twist. Used nothing but Varget so far with various bullets and this thing carbons up alot more than anything else I have. This is my first 6br but I use Varget in quite a few other rifles and don't experience this in any of my other stuff. It's not a copper collector but it sure does hold on to carbon. 2 patches wet with Butch's 3 down and backs with a wet brush, re wet and 3 more down and backs, follow with a wet patch and then 2 dry ones, soak it down with wet butch's patches, let it sit and dry it out and it's clean. I have gotten away from brushing because I haven't needed to in my other guns. Is there a way to limit the build up or am I just going to have to live with it?

 

[uncleduke]

My questions are just to get an baseline to the fouling. What is your load? Bullet/ brass/ primer and grains of varget. Low charges of powder can lead to more fouling. A typical load with lapua brass and cci450 or br4 primers is around 29.5 to 30.5 grains of varget. With this information we'll have more to go on.

 

[LRPV]

I have been working up to the charges. Using Lapua brass, CCI 450. Today I shot 5-105amax with 30.1 Varget and 15-95 Berger vld with 30 to 31.2 grs. Velocity seems slow compared to some of the loads and velocities listed on the home page here, but maybe it's just the difference in equipment and components. This is a 28" Mcgowen and the 31.2gr Varget and 95Vld was 2971 average (only 3 shots) with 10fps spread. I have been trying to get 105 Hornady Amax to shoot but I finally gave up today. I did start at 27 grains with the 105's but that was just minimal for a starting place. The one thing that I left out is that when I'm done cleaning, I run a patch with CLP down the barrel and then run one or two dry ones to get most of it back out. I do this with a couple of other rifles without issue.

 

[Kenny474]

I have heard a lot of others with the same complaint in McGowen barrels, not necessarily in 6BR, but just McGowen barrels in general. It was brought up on another forum, and I have read of it elsewhere when deciding what barrel to buy a while back. I don't think McGowen hand laps their barrels, as I have read that they don't in several places. So that may be part of the cause.

Here is another instance: http://savageshooters.com/SavageForum/index.php?topic=31541.0

Tubb's Final Finnish will help smooth out the barrel, and should make it foul less. It helped a factory barrel I have, and improved grouping as well.

 

[lpreddick]

LRPV: been there done that! my first 6br bartline shot one holes during load development
, then starting spraying. after getting clean patches with hoppe's, i tried a brass brush and WOW! CARBON that would not come out with wet patches. finally got the bore clean and the one hole groups returned ! had the same thing happen with my 22br and can only surmise the ballistics of the 6br case(not my 223 ackley or 243 ackley) promote carbon deposits. wish i had a bore scope. maybe those with a scope can enlighten us as to where this carbon is deposited and which cases are more prone to doing so. i doubt it is a powder, bullet, barrel or bullet coating thing.

if i can see you, i can touch you,
bang!

 

[LRPV]

Kenny, McGowen claims to hand lap all of their barrels. I believe this one was as it was smooth and didn't copper foul. I broke it in with a shoot one/clean process then moved to shoot 3/clean. When the copper was no longer visible I extended the number of shots between cleanings. After 11 rounds and cleaning the copper fouling was non existent or at least it went away with the carbon and didn't show up on a patch.
Lpreddick- The only thing it sprayed was the 105 amax. It's a .237 bore and the amax is the skinniest bullet I have to try and I am assuming that is the problem. I expected to see it group just as well at 200 with the 105 as it did at 100, but it just sprayed those 5 rounds. I am going to concentrate on a different bullet now.

 

[RonAKA]

Have you tried KG-1 cleaner for carbon removal? Testing reported at the link below, found it was the best at carbon removal.

http://www.frfrogspad.com/cleaners.htm

 

[LRPV]

Ron- I have not tried it. I am able to get it out ok and I'm not sure that it is affecting accuracy I was more looking for a way to minimize the fouling. The first couple wet patches before brushing push out small slabs of carbon. I guess I have just never encountered this before. I don't have the ability to compete in any matches I just enjoy shooting and try to make things shoot as good as I can.

 

[old_gasgunner]

For your information I have noticed similar extreme fouling in my 6mm Hagar (7.5 twist Krieger) using Varget powder. I just could not get it clean after shooting an 80 shot match. Another Hagar shooter told me to try VV-N140 and now I can clean with just patches, only brush it every 300 rds. Even the bolt is much cleaner. Don't want to start a bunch of arguments, but I believe Varget powder is very dirty in my gun. N140 shoots just as good groups also.
Tom in Michigan

 

[LRPV]

I have an 8# of N-140 but haven't seen any loads for it in a 6br. I now use it in 22-250 and it shoots great but I have never noticed it fouling anymore or less than Varget in them. I can get it to shoot the tightest groups in those two rifles.

I am having a hard time loading for this 6br as well. Going by what limited information there is in the Sierra and Hornady books, what there is on the Hogdon site, and what is listed on the home page here I have worked up to what is listed as the max and in a few cases gone quite a bit over that and I haven't seen any pressure signs yet with anything I have tried. This is one odd little case for me. With "normal" calibers close to book max or just a little bit over and it will let you know, but not with this one.

 

[dreever]

Try increasing the neck tension by going to a smaller bushing. That coupled with seating into the lands will increase pressures for a cleaner burn.

 

[LRPV]

I am using Forester FL sizing die so I don't have the bushings. It seems to be getting a little better on the fouling. I have not cleaned it yet after today though. Best load for me so far has been 95 VLD Berger, jammed .015 with cci 450, 31.2 Varget they are running 2970 fps and My barrel is 28". It is still not as good as I expected at 100 and 200 yards but it is staying together at 400. I may have to invest in one of those tools to sort by bearing surface. I forgot the chronograph at home today but yesterday I was running 107 SMK up to 30.1 Varget CCI 450 with those jammed .015 as well. They were going 2866 fps. Today I ran up to 30.9 grains Varget with the 107's and still not getting a hard bolt lift or marks and the primer edges are rounder than the load with the 95's. If things held true as far as powder increase to velocity as it did yesterday than the 107's should have been around 2925 with the 30.9 charge. Sierra's book max for those is 29.4 it just seems to me that I would be getting in trouble especially with this small case by now. I will have to measure the COL on both of these as I never remember to do it. I just worry about not seeing the signs until it's too late now. I guess I'll just stop where I am and make it work.

 

[Kenny474]

One thing to remember with Varget is that is varies a bit from lot to lot, and one lot may be faster than the next by a good amount. Maybe you have a slower lot and that's why you are getting less velocity than you expect and are not seeing pressure signs? Also, the Bergers may be a little bigger in diameter then the SMK's, as that will lower pressure with the SMK's a bit as well.

Also, max loads in most manuals are very conservative, as they need to be just as safe in a full custom as they do in Jim-Bob's old clunker. I am not saying to pay it no mind, but that often times you can cautiously exceed the max by a good bit in a high quality gun with a tight chamber and good brass before you start to see signs of excessive pressure.

 

[fdshuster]

Hodgdon's Reloading Manual lists loading data for the 6BR for all bullet weights from 55 to 107 gr. I've tried several of the listed loads on the 6BR info page, and they have all proven to be excellent.

 

[1000yardstare]

Am going to build a 6BR this Winter on a Rem 700 action and a MacLennon 30 inch 8 twist barrel so am following this thread with interest.

Have never understood the "universal" fascination with Varget. Have tried several powders with similar burning rates such as IMR 4895, H4895, RL15. Have had excellent results in .204 Ruger, .308, .223, .220 Swift, 6.5x55 with light bullets.

An F Class buddy was loading 140 Scenars in a 6.5x55 with loads of Varget that only filled half the case. He heard everyone talking about this miracle powder Varget so he figured he had to use it. He has since switched to a .308 where Varget makes more sense.

 

[LRPV]

I have only tried varget so far in this gun because it seems to be the go to powder for the 6br. I have used it with good results in 223 with heavy bullets, 22-250 from 40 to 69gr, 243 with some of the lighter bullets. I also like Viht N-140 a lot in all of these and I also like H4895. I have stayed away from most of the ball powders because of the myth/fact of them being so temperature sensitive. I am careful not to let my ammo sit in the sun, but we do our testing and load development when time allows and we coyote hunt all winter which can be -20 to 65 degrees or so. I like to use Rl-22 with heavy 243's, 7mm mag, and 300 mag but I am going to stop because my come ups don't work in the fall and winter if I worked it up during the summer.

The Hodgon book lists 29gr Varget as the max and lists it as a compressed for the 107smk. My OAL for the 107 is 2.4055 and the cases were once fired Lapua. They were pretty full of course with 30.1gr but not compressed. My OAL for the 95VLD is 2.425 which barely leaves enough of the bullet in the neck, but they seem to shoot ok so far anyway.

 

[chino1969]

I have three tight necked 6mm BR barrels. A 1:14" Hart, a 1:7.5" Kreiger and a 1:8" Kreiger. All three have had Varget in them. My cleaning regimen consists of the Wipe Out line of products including Carb Out and only stiff nylon brushes. I do have a borescope and use it to check for cleaning effectivess as well as throat inspections. I have no problem with carbon.

Chino69