6mm super lr build

[coyotehunter]

Gonna be building a new rifle finally decided to go with the 6mm super lr my gunsmith received the reamer today. Was wondering if any one had any suggested loads and I am going to use a Broughton 5c standard palma barrel with the 1in7.3 twist.

 

[rcw3]

As twists go a 7.3" is real close to the edge of the point of no return. We ran a few 7" twist barrels a few years back and they were too tight a twist (generated lots of pressure with moderate loads - rifling more like a wall and less like a ramp). I don't know how close 7.3" is to the edge, but it's got to be real close. 7.5" twist barrels have not generally been problematic - even though it seems like we're down to "splitting hairs".

I don't know what you are looking to do but H4831SC, N160 and RL19 have been great powders for a number of shooters using the 6mm Super LR.

Robert Whitley

 

[kperry]

You can find some data by searching "6 mm Super X", or" Super LR". I built one back in the spring, and used a 7.5 twist Bartlein . Make sure to use Winchester or Remington brass, weight sorted and good prep results in very good brass. I've worked primarily with the 115 Berger VLD, cause my primary use was mid and long range prone competition. I've
seen better results with the slower powders..- N165 , RL-25 , where I can get almost full case capacity with moderate pressures and good velocity , along with good accuracy too of course. Shot a 8 shot test group at 625 yds with N165 that was 1" tall by 3" wide. Will be working with this cartridge more in the coming months , but it seems to shoot several loads all in the same group. You definitly have to shoot ladder tests at 500 or 600 yards to see any real seperation. Good luck

Keith P.

 

[johara1]

rcw3, Did you have any problems with the 8 twist Bartlein with the 115 DTAC.?........jim

 

[coyotehunter]

If 1 in 7.3 is to fast will a 1in 8 work with 115 grain bullets. I don't know if Broughton makes a 1 in7.5 in the 5c rifleing. I have used 1in8 twist and thats what my 6br is but i only shoot up to 107 grain bullets.

 

[Raptor]

I had a Kreiger 1-8 in the SuperX and I used H1000 with the 105s and 115 Bergers. I mostly shot the 105s because they shot so well in it. Its an easy round to load for.

 

[TheBlueEyedBear]

I have a Bartlein 1-8 twist, 30 inch barrel on my 6SLR. I am currently loading the Berger 108's with 4831sc and it is really shooting great. I have some new loads to try once the weather changes here in Montana.

 

[tmr]

You shouldn't have any problems with the Broughton 1-7.3 twist. I run 115 dtacs at 3250fps with mine and it shoots sub 1/2moa out to 1k easily. Also shoots 105 bergers at 3350 sub 1/2moa. I believe its in the land design. The 7 twist cut barrels just seem to run into problems quickly.

 

[rcw3]

I don't think the 7" twist problem is related to cut rifled vs button rifled barrels as two of the 7 twist barrels we had problems with were button rifled. I also question whether land design is going to somehow solve a situation where the twist is too tight for the bore size (as I believe a 7" twist 6mm to be). I guess if someone wants to experiment a play to find out they can, but it was an expensive lesson for me (an inadvertent one because I did not know there would be problems with 7" twist barrels going into it). I have no desire to repeat that one.

Robert Whitley

 

[1shot]

I have a 7.75 Krieger and a 8 Broughton in this caliber. The 1-8 shoots the DTAC's with H-1000 great, and is a no-brainer to tune. The 1-7.75 gets a steady diet of 115 JLK's. Unless the winds are really switchy either cartridge will run with my 6.5x284with 7 gr. less powder and not make me feel beat up at the end of the match.
I hope this helps,
Lloyd
BTW, thanks for a great cartridge Robert

 

[coyotehunter]

rcw3
Do you think I will be ok with a 1 in 8 twist shooting the 115 bullets. I shoot mostly 107 sierra's but want to try the 115 bullets for a little less wind deflection. What to you recommend?

 

[Bob3700]

I am using a Bartline 5R with a 7.5T with the 243 SLR. It is used exclusively for 600 yd and 1K competition.

Brass is all new sorted Winchester.

Most of my loads are with the 115 DTAC (Hbn coated). Have had success with H4831sc, N165.

For the 105B or 107 SMK, I will shoot H4831sc or N160.

My loads are not real hot. The 115s are right at 3000 fps and the 105s are 3150 fps.

All will post as high a score as I can shoot. The 115s are right there with a 6.5x284. Very flat shooting and low wind drift.

I don't shoot the 105-107 gr bullets out of it that much as my 6mm BRX will drive them at 3050 fps with 10 gr less powder. That extra 100 fps isn't worth it to me.

Bob

 

[rcw3]

rcw3
Do you think I will be ok with a 1 in 8 twist shooting the 115 bullets. I shoot mostly 107 sierra's but want to try the 115 bullets for a little less wind deflection. What to you recommend?

The 1:8" twist is a bit close in stability factor with the 115's (I cannot say it will not work, especially for the DTAC's, but it will be very close for the 115 VLD's). With the 115 DTAC's, I had a Broughton 1:8" twist that would not stabilize them, but a 1:8" twist Krieger (a true 8" twist) that would. Honestly Broughton's 8" twist was not a true 8" twist (great for the 105-108 gr bullets but not the 115's). If you use an 8" twist, make sure it's a true 8" twist. Bear in mind the original Berger literature from years back had a 1:8" twist as the recommended twist for the 115 VLD's and in summer conditions and not at sea level you might be fine.

One of the keys with shooting the 115's is "walking the fine line", not too loose a barrel twist, not too tight. Maybe the 7.3" twist is o.k., but it's just tight enough that I would be concerned (maybe not rightly so). I know true 7.5 twist barrels are fine (had a lot of them and never had an issue), and I have had good results also with 7.8" twist barrels and the DTAC's, but I now tend toward the 7.5" twist for the 115 VLD's.

Robert Whitley

Add On - - Looked on the JLK website last night and their "optimum twist" for their 115 VLD is listed as a 1:8" twist.

 

[RayPrager]

Hey Guys ... On a different note ..I have been looking into a 6mm for a Long Range Gun ,1000 yd .But I'm wanting to Build a Pistol .. 15" /18" barrel ,8 T ...how would you all stack this up to the 243AI or the 6x47 Lapua.. I'm sure this has been discussed but ,this is going to be a Pistol ..
thanks for any help
Ray