Reply with quote #17
6BRX long range project update.
I've completed testing with Re-15 this past wk. I couldn't get the accuracy or low ES as I could with Varget. So I dropped the powder.
During load testing I found the 105's run about 50-75 fps faster than the 107's with the same charge wt. My testing is complete with med. burning powders: 4064, Re-15 and Varget. My current top load is 32.5 gr. Varget, 105 Bergers, Fed. 205 match primers. 10 shot ES is 9 fps.@ 3080 fps out of a 31.5 in Broughton barrel. 10 shot groups at 100 yds. run from .38in to .5 in. This is going to be my 1000 yd. load for the NC state long range champships.
I also tested 3 slower burning powders, VV540, VV550 and H-4350. I will post velocity, accuracy and ES data on the next thread. Untill then, good shooting.
Reply with quote #18
6Brx loading update.
Here are the results of my vel. testing using my 31.75 in Broughton barrel:
2 shot avg. VVN550 31 gr. 2927fps 31.5 gr. 2952fps 32.0 2990 fps 32.5 3048 fps 33 gr. 3047 fps 33.5 3084 fps and 34grs. 3122 fps. None of the cases showed pressure signs.
VVN540 31 grs- 2963fps 31.5 grs. 2981 fps. 32 grs. 3030 fps 32.5 grs. 3058 fps and 33 grs. 3110 fps. Again, no pressure signs, but I thought, based on vel. that both loads were probably max. in my gun.
H-4350 31 grs. 2825 fps 32 grs. 2850fps 33 grs. 2910 fps 33.5 grs. 2968fps 34 grs. 2991 fps. 34.5 grs. 3038fps 35 grs. 3070fps. No pressure signs. Comments: I tested the loads individually for accuracy. All loads tested were in the 3080 fps range. Using 105gr. Bergers, none of these loads equalled Varget for accuracy or ES. so I'm sticking with Varget for now. John Skowron
Reply with quote #19
6BRX at 1000 yds.
The final test for my 6brx project came at the NC LR state championship, held at Butner. The championship consisted of 4 1000 yd matches, held over 2 days. The winds ran 15-25 mph on day one, and 10-15 mph on day 2. I couldn't believe how well this cartridge performed in the wind. I shot in the 190's for all 4 matches. I placed 5th overall among sling shooters. I was shooting in the any/any class and was placed in F- open, where I placed 2nd. I did not feel handicaped compared to the 30 mag. or 6.5-284 shooters. I was squadded with anouther high master shooter, using a 6.5-284 with 142 gr. mk,s. During the scope phase of the compitition we were both shading the 10 ring with 2.5 moa windage on our guns. Wind drift with both rounds appeared to be almost identical. The points I lost were to poor shot placement or wind calls, not to the 105 Bergers being blown all over the county. Anyone what to buy 260 dies? John Skowron
Reply with quote #20
Remaining 6BRX Projects
Now that I know the 6 BRX is competitive at long range I'm retiring
my 260 Rem. However, I still have several projects remaining regarding this cartridge:
Fireforming loads, How far do I need to jam the bullets into the lands when forming new brass? 60 thousands in resulted in 7 split necks out of 110 cases. My next experiment will compare 50 thousands in the lands vs 40 thousands in.
Multiple primer test for accuracy and ES.
Faster powder testing. Namely, H322, Benchmark and H4895.
As my test results become available I will put them on the site.
Reply with quote #21
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.
a/k/a Nathaniel G. Lambeth, Sr.
Custom Guns and Ammunition
Reply with quote #22
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.
Reply with quote #23
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.
Reply with quote #24
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.