John708's Project has started

[Rustystud]

Friends who are following Johns708 Project:

John Skowron has been a high master shooter for several years both XC and LR. He has literally shot out about 6-8 barels in the 260 Remington as I know have set back or rebarreled at least 4. Last year John came to me with his idea of developing a 6mm centerfire rifle that would be a win, win, win. His theory was better inherent accuracy, less recoil, less expense and better barrel life without giving up much if any BC and wind bucking ability. John read and studied the 6mm postings in every forum on LR and High Power for about 3 years. John has proved each of his theories and is still building on them. I am now in the process of rebarreling a second 6mmBRX for John. We both believe he will get between 2500-and 3000 rounds out of his first 6mmBRX. His first rifle has about 1400 rounds down the tube and is still shooting better than any of his .260s. John and I are firm believers now that the 6mms will dominate the XC and LR shooting of the future for the very reasons John choose to shoot it. I am of the belief the 6BR, 6BRX, 6Dasher, 6XC and 6 X 47 will be the rounds of the next decade. I thank John for his work and dedication shooting the 6BRX. He has fired close to 1400 rounds. He has documented and kept good records. If you ask John a question about the 6mmBRX he can and will give you and educated answer. John has proved you can take an inexpensive Savage Model 10 and shoot it with the best custom actions and it will hold it's own. Thanks to Bob Crone for coming up with this cartridge, Thank you to Dave Kiff for making the gages and that fine reamer. Thanks Tim North, for that Broughton barrel, the one with the with a spot in it. I hope my next barrel looks like a leopard. Hummers only come along a couple of times in ones life.
Rustystud
a/k/a Nathaniel G. Lambeth, Sr.
Custom Guns and Ammunition

 

[Rustystud]

Folks:

I cut, turned, threaded, chambered, cut, crowned a second Broughton 6mm barrel for John708 on a second Savage Model 10 receiver. This one will be an inch shorter at 31" John still stayed with the Savage barrel nut configuration on the 1:8 twist, 5C barrel. This one will start out 1.250 and taper to .920. I changed out Johns old bolthead with a new style and had to also change out the firing pin. I radiused the bolt lugs leading edges and lapped the lugs for bilateral engagement. The cocking piece pin hole in the bolt body has been recut for lighter lift on cocking. The entire bolt has been polished and retimed. The SAV-2 Rifle Basix trigger will be on about 6 oz. It will be interesting to see how it shoots com[ared to Johns first 6mmBRX. I am sure we will keep you posted.
Rustystud

 

[JOHN708]

6BRX project update

I've got 1900 rds through my 6BRX and the gun is still shooting well. .42in 10 shot groups at 100 yds. with ES of under 10 fps.

I 've performed some additional experiments regarding bullet seating depths while fireforming loads. 40/1000's in the lands seems to be the optimal depth, no cases lost with 85 rds fired.

I've tested Benchmark and H-4895. Benchmark was just too fast, Max. vel was just at 3000fps with the 105's, so I dropped this powder. H-4895 with CCI-br-4 primers, with 105 Bergers, 31.75 in barrel.
30 grs. 2973 fps. 30.5 3015 fps. 31 grs 3044 fps. 31.5 grs 3082 32 grs. 3091 fps with very slight ejector marks. 31-32 grs. loads were tested and didn't group as well as my current load of 31.5 grs. of Varget and 105's at 3060 fps. I plan on doing more load testing this wk. Results will follow.

John Skowron

 

[Rustystud]

Folks:

Before John708 Introduced me to the 6mmBRX I had never hear of it. I knew of the 6BR and the 6 Dasher. I had shot groundhogs for years and knew there was a significant improvement in the 6mm over the 22cal from 400 yards out. In the last 10 years there has been significant improvement in bullets, powder, brass, and primers. The elements long distance shooters also were dealing with was recoil, barrel life,and cost. Over the last few years we have seen a movement from 30 caliber, to 7mm to 6.5 and now 6mm. The BR shooters have always been like the formula one race car drivers. The LR shooters have neen the NASCAR level and the varmint hunters and wildcatters have been the outlaws.

John has shot 30s, 7mm, 270s, 264s, and now 6mms. His goal was to find an inherently accurate cartridge from the get go. This cartridge needed to be fully capable of keeping up with the 6.5s and 30s. It needed to also be more shooter freindly, reccoil, component friendly, cost wise, and have longevity.
Now in todays world this means most likely one caliber.

The 6BR, 6XC, 6BRX, 6Dasher, 6 X 47 Swiss, and the .243. All have their good and bad points. The 6BR is just not got enough horsepower and the .243 is just too much horspower. The 6XC is propriatary and more costly to shoot. The 6 X 47 is new to the US market and component have been difficult to obtain. The 6BRX and Dasher are off shoots of he 6BR. The basic difference is the shoulders. There are many variations of different neck length and diameter. The advantage of the 6BRX is one can use 6BR dies to load it and it chambers a little more friendly. It also is a no neck turn cartridge. Lapua make great 6mmBR brass. Berger and Sierra make great 6mm VLD bullets. The cartridge is more effecient and easy to put together. Another factor is barrel life. You are shooting in the 3000 to 3100fps which is in the accuracy and effeciency node. Tim North of Broughton barrels and I talked at length about the 6mmBRX and Dasher. He tells me that John may get 4000 rounds out of his barrel. Johns expectency is 2500 to 3000. that is 800 more than one would expect out of a .243. If John gets 4000 it will greatly exceed his expectations. As stated in a previous post I have barreled up a second 6BRX for John as a back up gun. I currently have a customers gun in my shop that is a 22BRX. I am doing a little testing with it and it too is looking very promising to be a longrange contender. I was so impressed with Johns results that I am building myself a 6BRX. 2007 should be an interesting year for both BR and LR shooting crowd. Guns are becoming more fun and less expensive to shoot. Not to count out more accurate. The 1000 yard group record was broken at least twice last year. Both times I believe it was a 6mm cartridge taking the win. I thank Bob Crone and others did us a great service introducing the 6BRX.
Rustystud
Rustystud

 

[JOHN708]

Pierced primer problems, and new load testing.

I've been having problems lately with pierced fed 205's behind 32.5 grs of Varget and the 105 Bergers. This load has always caused an occasional pierced primer. This hasn't been a problem up to now as my primer pockets have always been tight. I got 15 reloads out of the Lapua brass before the primer pockets started to loosen.

I think the problem is related to either a batch of slightly softer brass, or some throat erosin raising pressure slightly. Before playing with JB bore compound or Tubb's throat maintance system, I thought it would be prudent to go back to the harder cups of the CCI br-4's. I did a ladder test with H-4350 and the CCI match primers in my current rifle. The velocity data is listed below:

34 grs-3030 fps. 34.5 grs-3066 fps. 35.5 grs-3110 fps 36 grs-3145 fps. There were no pressure signs or pierced primers with these loads. I shot a 5 shot group with both 35.5 grs- .37in at 100 yds. and 36 gr. .45in at 100 yds. I'm going to test the 35.5 gr. load against my current long range load on Sat. I'll post the results when I done testing.

John Skowron

 

[DukeDuke]

Great thread John!I really like the performance of the 6brx. Keep us posted how it goes with 115. You think you can get it around 3000f/s?

Thanks!!!

 

[Cheaha]

Yes, Please continue. Great thread and info...

 

[JOHN708]

6BRS Load Testing update:

I shot some 10 shot groups at 100 yrs. yesterday, comparing 35.5 grs. of H-4350 vs 31.5 grs. Varget,my standard comp. load). The 4350 load was behind CCI -br-4 primers. Both loads were shot with Berger 105's jammed 15/1000's in.

The Varget loads consistently grouped in the .4's at 100 yds. The 4350 loads would shoot really well for 8-9 shots, but in that group there would always be 1-2 flyers, opening the group up to .6-.7 range. So I'm staying with Varget and Fed. 205's until the barrel burns out.

As far as shooting the 115's goes, I've temp. abandoned the project. The 105 Bergers, running 3050-3100 fps. gives up very little wind drift to the 115's running at 2900-2950fps. You might potentially get 3000fps with the 115's using H-4350 and throating the chamber to seat the bullets out. But since I'm very happy with the 105's and the way their performing at long range, I'm not going to change for now.

John Skowron

 

[DukeDuke]

Thank you again for the update! I see your point with 115s and agree. Running 105 at 3000+f/s is very competitive. Now, at that velocity, what is the life of the brass?

Thank you!

 

[JOHN708]

6BRX case life questions answered.

Case life running the 105's at 3000fps+ is 14-15 reloads. Brass was discarded when the primer pockets became too loose. The 6BRX brass OAL after fireforming is 1.56 in. Max OAL for the 6BRX is 1.58 in. The brass never stretched enough to require trimming before dischard. Anouther plus for the 6BRX and Lapua brass.

By the way don't even bother with Rem. 6br brass. The primer pockets were so loose after my standard fireforming load I had to trash all the cases. Stick with the good stuff, Lapua.

John Skowron

 

[DukeDuke]

Brass life is as good as it gets. Great news!

Thanks John!

 

[JOHN708]

6mmBr project update

I now have 2570 rds through my 6mm brx. I was just at the range today doing an accuracy test. 2 10 shot groups, 1 with 105 Bergers, and the other with 107 Serria's were shot at 100 yds. Both were identical .44 in groups. Not bad for a rifle with 2500+ rds through it.

Achieving this barrel life goal pretty much completes my 6mm brx project. I'm now shooting a cartridge that has the same or better barrel life than the 260 rem., it's more accurate, with essentially equal wind drift. I'll continue to post updates on barrel life. I think this barrel will last for anouther several hundred rds. I'm also in the process of working up loads for a second 6mm brx. I will post that data when it becomes available.

John Skowron

 

[Rustystud]

John did not tell you these last 10 shot groups were shot with the Lot# 559 105 Bergers. He did not tell you if he had been shooting 5 shot groups they would be in the low 2s.

This says a lot for the 6mmBRX but it says a lot for Broughton Barrels, and Savage Actions.

John also did not tell you he was the overall 1000 yard winner at Butner back in February 07. There are a number of very experienced shooters begining to take notice of John's project.


Rustystud

 

[JOHN708]

match correction

To set the record straight, I wasn't the overall winner at the North State shooting club championship in March. I shoot any-any exclusively at long range. I was the overall winner during sunday's 1000 yd scope match. I had the high overall score for the two day match, but since saturday's match was aperature only, I didn't qualify for the overall championship. Kent Reeve won the overall championship.

John Skowron

 

[JOHN708]

6mm BRX barrel wear update

I now have 2900rds through my 6mm BRX. I was doing some load testing with the new 6mm Berger bullets. I compared them with my existing comp. load in my 6mm brx.

The 105 gr. Berger's, jammed 15-1000's into the lands, with 31.5 grains of Varget and Fed. 205's are still shooting .45 10 shot groups at 100 yds. Vel 3060 fps. I don't know how long this Broughton barrel will last, but I'm amazed that it's lasted this long.

As far as the new Bergers go, The 105's grouped as well as the old 105's. The 107's and 108's didn't do as well in my particular gun. I will continue to post updates on barrel life with this project gun. Good shooting.

John Skowron

 

[DukeDuke]

Thank you for keeping us up to date! It is truly appreciated!

 

[Rustystud]

John Skowron will be bringing some interesting news about his #1 6mmBRX. He just surpassed the 3000 round barrier and the throat and accuracy evaporated in twenty rounds. He spent a good portion of the day in my shop debugging the new 6mmBRX gun #2. After correcting some chamber and stock bedding issues John shot one group with 108 Sierras that was .19". This gun also is a Model 10 Savage and Broughton 1:8 5C barrel, in a Kevin Rayhill,Stockade Stocks) Elk model thumb hole Stock. John will be loading tonight and returning to the range in the morning. It will be interesting to see how the second gun in the new stock compares to the first.

Rustystud

 

[JOHN708]

My 6BRX project gun testing is complete.

I had virtually no throat erosion until I reached 2900 rds. The throat became noticeably rougher on cleaning and opened up 2/100's of an inch. 10 shot groups with match ammo were .53 in. At 2950 rds. the groups ran .58 in. At 3044 rds. the groups opened up to .7 in. not enough accuracy for LR work. Useable accuracy with this gun was 2900 rds.

I started my 2nd 6mm BRX LR gun project. The initial results look promising. I will report on any new problems, load development, etc. as data becomes available. Until then, good shooting.

John Skowron

 

[Rustystud]

Johns 2nd BRX project is Southpaw Savage Model 10 still using the barrel nut. His second barrel is a 31", 3.5" 1.200, to .900, Broughton 1:8, 5C, barrel. The stock is a Stockade Thumbhole Elk model. It has a three way adjustable but plate, an adjustable cheek piece and a hand stop track in the fore stock. The stock was pillar bedded by Kevin Rayhill at Stockade. I opened up the lug well and reglassed it with a mixture of fiberglass resin and polyester filler. The lug and tendon area were completely filled then the action was pulled down onto the pillars. John was having some fliers in preliminary test hopefully this will end the flyers. The 11 degree crown was cut with a piloted 79 degree PTG counterbore made by Dave Kiff. The crown is recessed about .100 for protection.

After John and I work together to get the bugs ironed out he should get another 2900-3000 round barrel life from this barrel. I was so impressed with his first 6mmBRX that I am building one for myself on a trued Remington 700 SA.

Rustystud

 

[JOHN708]

Load data for IMR 4007SSC in the 6BRX

Recently I ran some IMR 4007 through my 2nd 6mmBRX, in an attempt to achieve more velocity through this particular gun. Broughton 31 in. barrel. I used 105 Bergers, jambed 15 thousands in the lands, behind CCI-Br4 primers. Load data as follows:

IMR 4007: 33 grs- 2892fps
33.5 grs-2968fps
34 grs.- 2965fps
34.5 grs.- 3043fps Note: Max for this particular gun with slight ejector marks showing.

Comments: I tested 34.5 grs. in my gun at 100 yds. Disappointing group, 1 in. for 5 shots. Varget groups way better in my rifle with essentially the same velocity and lower pressures. I think 4007 might be a tad slow for 6mmbr and BRX cartridges. I'm going to continue with Varget and Re-15 in my BRX for the time being. Good shooting.

John Skowron