6mm super LR F class gun "range report pics"

kombayotch said:
I'm probably going to chamber a rifle in either this caliber or a regular .243 Win. (throated for 115 DTACs) just see how it compares to my 6mm Crusader. What are your barrel and reamer specs, if you don't mind my asking?
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The barrel is a gaillard HV 1-8 twist 28" and the reamer is a no turn neck .275 with .120" freebore from Dave Kiff at ptg .

I sized up a few pieces of brass and I will have to shave the necks a bit I ended up with .276 with a bullet in it ,so that is perfect I didn't want to much clearance :D.
 
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Is it a .236 bore or a .237? I've ordered a Bartlein 5R .237/.243 M40 1-7.5 twist. 5R rifling and .237 bore is the way to go if you want to run the 115s really fast with less chance of blowing them up.

roberti11 is going to give me some brass on the weekend so that I can load up some duds and see if I can strip-em out of the mag quickly without feed issues.
 
I was checking what size pilot I needed and it looks like .2364 or .2366 I was going to run a 1-7.5 twist and decided to try a 1-8 I am planing to shoot 105-108 gr .
 
My 8 twist barrel should be in my hands soon and by late fall I hope to be able to order my "Obtunded improved" 6slr reamer. As he stated earlier, the neck is a little sloppy and I am hoping to tighten that up just a bit with Obtunded's recommendations.
 
Shooter ----/ said:
My 8 twist barrel should be in my hands soon and by late fall I hope to be able to order my "Obtunded improved" 6slr reamer. As he stated earlier, the neck is a little sloppy and I am hoping to tighten that up just a bit with Obtunded's recommendations.
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What is the diference between the 2 reamers is it the shoulder angle?
 
He sent me a reamer print with changed neck diameter, if my memory serves me correctly, it would save the brass in the neck area from being overworked.
 
It wouldn't be the shoulder angle...

When I design my reamer, it will around re-sized cases from the sizing die I plan to use, which is usually a Redding S-type FL die. Tight necks have always given me more issues that looser ones, in hot rounds. Any hint of a burr left on the case mouth causes a pressure/velocity spike. Easy enough for the benchrest shooters to avoid because they're playing with relatively few cases vs. loading hundreds or thousands at a time.
 
Whitley's reamer specs out a .275 neck. That is ok if you are using magazines, but it is a bit sloppy for the ultra-precision market. This is a case you will very definitely want to neck turn, (You are converting shoulder to neck meat, not the other way around) and without turning, the .275 neck on anything but lapua brass will be SAAMI and beyond.

As to the 236 versus 237, remember that is the land diameter. For best obturation, I have always found that with anything 100 grains and above, you want 236.

For cartridges shooting flat based bullets with drive bands, the 237 is a nice fit, but for boat tails and long bearing surfaces, 236 is - in my opinion and based on my own experimentation - much easier to make work.
 
redshooter said:
I'm curious, why not a 6mm Rem AI?
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A 6mm rem ack imp is a great round imo but it has been tried and I want to try something different ,I also wanted a 30 degree shoulder which is proven to be accurate .
Also the long neck of the slr was something I liked it is kind of like a long br.
 
coyote said:
A 6mm rem ack imp is a great round imo but it has been tried and I want to try something different ,I also wanted a 30 degree shoulder which is proven to be accurate .
Also the long neck of the slr was something I liked it is kind of like a long br.
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So I'm assuming the 30 deg shoulder is opt. :)D if so you learn something new everyday!). So if I wanted to do a 6mm Rem Imp, a 30 deg shoulder would theoretically give better accuracy over 40 deg.
 
I do not have much data on mine, but Iwill post what I have, I had intended to use it as my short range rifle at the Ontario Provincial ORA match, but got sidetracked building a platform to shoot the .277 175gn Matrix VLD's.

I shot about 60 rounds with my 6mm LR super, I used a .272 neck, otherswise the reamer is the same as posted by Whitely.

I have a shillen Select 1:8 twist 30 inch bbl and I was shooting 117gn Matrix VLD's using N560

Max Velocity was 3263 using 46 gn, the most accurate node in my limited testing was 3155 fps, using 44.6 gn, the vertical at 300 yards was well under 1 inch, actually close to 0.6, but this was only 2 five shot groups, I need to do more testing.

I can confirm that Lapua brass is no good for this, as it develops a significant bump due to the thicker brass in the shoulder, I turned these and fire forformed only to see a donut re-appear, for my posted data I used weight sorted winchester .243 brass
 
redshooter said:
So I'm assuming the 30 deg shoulder is opt. :)D if so you learn something new everyday!). So if I wanted to do a 6mm Rem Imp, a 30 deg shoulder would theoretically give better accuracy over 40 deg.
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I don't know if it would give better accuracy, but 6mm Crusader is basically a 6mmAI with a 32 degree shoulder and a body taper that matches 308 Win. It has the same case capacity as 6mmAI. The idea was that it would feed from an AICS mag, which it does. However, there is a rib in the mags that is meant to prevent the rounds from shifting forward interferes with the shoulder and only 8 rounds can be loaded in a mag. I'm not liking that for ORA precision matches, which are always 10 rounds.

The barrel recently passed the 2000 round mark, and it still shots like this at 300 yards:

P1060111.jpg

Still under 2" with the flyer.

This is shooting prone off a Harris bipod, not a rest. The flyer may very well have been me or charge weight variation since these were loaded quickly at the range, I can't say for sure. In any case, its still good enough for ORA precision and sniper matches. I shot a 50.8 with it on the 600M deliberate at a match at Milcun a couple weekends ago. I didn't do any load development with the Matrix bullets beyond loading them to the same velocity as the DTACs I have been using. It seems to do a bit better with them and WW brass though.

Many people told me that by 1000 rounds the first 4" of rifling would be gone. It isn't yet. It has only a slight rounding to it at the throat. I haven't checked how much the throat has eroded because I've never adjusted the seating depth. It's stayed at magazine length the entire life of the barrel. I think the long neck and the 32 degree shoulder have played a role in the barrel life. The long neck seems to really help with runouts.

6 SLR should offer the same advantages with an even longer barrel life. It seems to be able to reach the nodes I am shooting and will not have the magazine limitation I am currently experiencing (although, I've been told that the 300 WSM AICS mags with the feed lips bent in a bit solve this problem). As long as feeding is reliable when working the bolt rapidly, I will probably move to 6 SLR for that application and build a single shot with the Crusader since it has a 150-200 fps velocity advantage in the same length barrel, with the bullet seated out all the way. I'm reaching max pressure with Retumbo and RL-25, so I think I might be able to squeeze out a bit more velocity with US869.
 
"Improving" is more about horsepower than accuracy. Depending on what bullets you use, you may run into a functional maximum velocity. I have found that Berger's VLD bullets max out at just under 3100 for accuracy. I could achieve much higher in an XC, but horrible accuracy. I could also get to 3100 in a 6X47L and a 243 and they accuracy simply was not there at all (105 grain bullets)

As to a 6 Remington anything, it basically needs a long action. If I were going that route, I would go 6-6.5X55 SE AI. Waaaaaaay better brass and easier to find. The dies are also easy to find too. Simply re-bush 6.5X55AI dies, and use a VLD seater.

It took me a long time to get there, but I have come to believe that there is nothing better than a 6BR or a 6XC for the 6mm game. EASY to make work, common powders, great barrel life and untouchable accuracy.
 
Obtunded said:
"Improving" is more about horsepower than accuracy. Depending on what bullets you use, you may run into a functional maximum velocity. I have found that Berger's VLD bullets max out at just under 3100 for accuracy. I could achieve much higher in an XC, but horrible accuracy. I could also get to 3100 in a 6X47L and a 243 and they accuracy simply was not there at all (105 grain bullets)

As to a 6 Remington anything, it basically needs a long action. If I were going that route, I would go 6-6.5X55 SE AI. Waaaaaaay better brass and easier to find. The dies are also easy to find too. Simply re-bush 6.5X55AI dies, and use a VLD seater.

It took me a long time to get there, but I have come to believe that there is nothing better than a 6BR or a 6XC for the 6mm game. EASY to make work, common powders, great barrel life and untouchable accuracy.
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Follow up question on 6BR and 6XC:
Can either be feed from AI magazine or any commercial magazine?

Alex
 
redshooter said:
So I'm assuming the 30 deg shoulder is opt. :)D if so you learn something new everyday!). So if I wanted to do a 6mm Rem Imp, a 30 deg shoulder would theoretically give better accuracy over 40 deg.
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I am not saying a 30 deg shoulder is more accurate but a 6ppc and a 6br both have a 30 deg shoulder and they both dominate there own world when it comes to accuracy.

My original idea was to build a wildcat based on the 243 case I wanted a long neck to hold the bullet good and I didn't want a barrel burner [torch efect of a short neck suposably].
I also wanted the same case capacity of the 243 to push the heavys and I didn't want to long a powder column , so I formed a few pieces of brass to the shape I thought was good and was ready to mail it in to PTG for a reamer when I stumbled on the 6 slr .

It was almost identical to what I wanted afew tous here and there so I ordered the slr reamer.
 
Well I got a chance to chamber it tonight only thing left is to cut the crown and bed it .
The reamer didn't perform very well it is only cutting on 2 flutes and a little on a third one I've had reamers not cut on all the flutes but not this bad.
 
Well I got out to the range today with it and am very impressed .

I was using some hornady 100gr soft points to fireform and my worst group was about 1/4" @ 100.

Once I had about 10 pieces of brass fired I neck sized a few and shot some one holers @100 a few times in a row some of the groups would have measured in the 0's .

I used some 4350 type powder that worked very well in my old 243 , next time out I want to try some 4831sc .
The velocity I chronoed was around 3000 with berger 105's with no pressure what so ever I could increase the speed by a few hundred feet for sure.

My 6br shoots great but I think the 6slr might be a tough contender if it keeps shooting like it was this evening, even with the slow speeds I was shooting it at tonight I was 150fps faster than my br and grouping as good if not better.
 
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