6xc grouping issue.

Longshot

Longshot

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So a while back I posted something along the lines of me having issues with my 6xc not being able to shoot under 1/2 moa on a consistent basis. I've gone through 115dtacs, 115 Berger Vlds, 108bts and finally 105 hybrids. I've shot varget, RL17, H4831SC and H 4350. Tried 210m and Br2s. I've seated it into the lands, out of the lands and everywhere in between.
The rifle itself is a Remington bedded into an A5 stock with a Bartlien 5R running 1/7.8 twist.

This thing has been a little vexing to say the least. I always felt it should shoot better than it does.

So today I'm perusing the Krieger website and I'm looking at 5R info and under calibers it states that they don't recommend 5R rifling for 6mm bullets! Doesn't say much more than 6mm bullets don't shoot so well with this type of.rifling.
Sooo...the big question for me is anyone else having issues with a 6mm with 5R rifling ...OR vice versa ....is anyone having incredible success?

Wondering if it's time for me to order a couple of new barrels.
 
I have a 1-8 benchmark 5R for my 6mm crusader and when I find a load for a bullet I have no issues with them. The 115 dtac's are great, I just can't find anymore. The 115 berger vld's are great as well, but to long of a bullet for the round for my set up. I have a bunch of 108 BT's that I am gonna mess with and go from there. Want 105 hybrids but pickings are scarce. My 115 dtac load at 52.5g retumbo fed 210M was not uncommon to have .25 moa groups. So not sure about 5R barrels and 6mm's. This one is my first and has been fairly "forgiving" towards me. Hoping the 108's preform like the other bullets....again, newer to 6's. Shot mostly 308, 223 and 300wm so just trying to treat it all the same with my reloading and kit and cross my fingers. Hope you get it figured out.
 
I have a gaillard barrel 1:8 twist but not the 5R rifling.I started with 105 gr bullets in nosler ,berger,lapua then hornady.They all shoot decent groups.
Stepped down to a 90gr lapua and got some nice groups.then tried a 87gr vmax that looks very good.
I use norma 203b powder and also tried varget.I'll post some pictures later of my targets with bullets and powder info.
 
Tubbs recomends a Gary Shnieder Polygonal barrel for the 6XC. I had one and it shot 1/8" groups with 115 DTACs at 100 yards. I'm not sure how the 5R should compare.

How is your scope?
I'm thinking you might have a paralax issue.
Do you know how to set paralax, because few people do?

I'll be brief...
When the rifle is set up at the range, set the rifle so it rests aiming at the target. Then without touching the rifle look through the scope and move your eye from side to side and up and down just a bit to see if the reticle stays on the same spot on the target. If the reticle is moving, then you need to tweek your paralax until it remains at the same point on the target. Only then do you shoot.

I have seen many many shooters shoot badly because they just dont understand paralax.
 
Ryan - let's get out to Mission and see how it shoots. If you wish I can bring a spare scoped rifle so we can change out your scope to determine if that might be an issue.
 
Any chance you know what the bore diameter is? 6mm is one of the few that can be offered in a couple of flavours - 236 and 237 (or whatever flavour is cooked up as the lastest greatest). Some SR BR groove diameter were also very tight to fit custom bullets - under 243".

So there might be a mismatch in bullets due to higher then expected pressures.

Assume you are running loads on the toasty side? Consider backing way off to starting loads and testing again. Might be as simple as that

Of course, it could be the other way where you have an oversized bore vs a small bullet. :)

Mic the bullet and see if they share the same diameter. compare to another brand like Hrn which tends to be "fat".

I had this with a 6mm BR way back when. Until I tried some "skinny" bullets, the barrel wouldn't shoot to save its life. But when the right fit was found, it shot awesome.

Hope this helps...

Jerry
 
BadAsMo said:
Tubbs recomends a Gary Shnieder Polygonal barrel for the 6XC. I had one and it shot 1/8" groups with 115 DTACs at 100 yards. I'm not sure how the 5R should compare.

How is your scope?
I'm thinking you might have a paralax issue.
Do you know how to set paralax, because few people do?

I'll be brief...
When the rifle is set up at the range, set the rifle so it rests aiming at the target. Then without touching the rifle look through the scope and move your eye from side to side and up and down just a bit to see if the reticle stays on the same spot on the target. If the reticle is moving, then you need to tweek your paralax until it remains at the same point on the target. Only then do you shoot.

I have seen many many shooters shoot badly because they just dont understand paralax.
Click to expand...
So I've realized I've left out tons of info. I've run 2 different scopes one is a Leupold Mk4 6.5-20 and the other is a S+B PM2. Both have paralax adjustments so I don't think it's that. Both scopes run just fine on my .308.
 
Tomochan said:
Ryan - let's get out to Mission and see how it shoots. If you wish I can bring a spare scoped rifle so we can change out your scope to determine if that might be an issue.
Click to expand...

Love too shoot it at 300 for sure. Maybe one of those 12-50s might make a difference.I'm not going to BN this bunch of 105s and run them naked to see if that helps. I've used both .268 and .266 bushings. No difference.

Jerry I'm not sure what bore diameter was to be honest. I am running them kinda toasty for sure. I did shoot a 75-9v at the farky and it shot ok otherwise but I just think it should be better. I'll definitely check bullet diameters but I would figure that with the amount of different bullets I've tried something would have worked.
 
You may find that these long bullets shoot BETTER on an MOA basis at 300yds then they do shorter.

I know, I know but have been scratching my head with my 223/90. Shoots better at 300m then at 100yds on an MOA basis.

Try backing down on your loads. There is also a chance that you bore has finally "broken in" and the actual node is a few tenths less powder.

Load tuning never ends and super high pressures just means you have to do this ALL the time.

If your rd count is approaching 800 to 1000rds, the pipe may also be getting tired.

Throwing a bunch of ideas out there as I know no clue on the history or useage of your rifle. But these are some of the things I watch for.
Jerry
 
Longshot said:
So I've realized I've left out tons of info. I've run 2 different scopes one is a Leupold Mk4 6.5-20 and the other is a S+B PM2. Both have paralax adjustments so I don't think it's that. Both scopes run just fine on my .308.
Click to expand...

Not to beat the point to death, but quality of a scope does not remove paralax nor does the mere existance of the adjustment knob. It still needs to be set correctly and visually verified when you shoot or any time you change distances.

Improper paralax adjustment can easily turn a 1/8 MOA gun into a 1.5 MOA gun.

Even when the parallax is set as close as eye can get it, I creep back from the scope just enough to see the fog lightly form around the outer edge of the field of view. I then position my eye in the center of that blur as an extra measure of certainty to ensure parallax does not factor into it.
 
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I've shot out several 5R barrels in my 6mm Crusader now and all have been tack drivers.

Problems with grouping often have to do with brass, particularly the case neck. If you have donuts at the bottoms of the necks or burrs at the mouth (using SS media?), groups will suffer. Here is a simple test: take some fired cases and try to drop a bullet into the neck. It should just fall in. If there is any resistance, fix the issue and see if that helps.

Since this is a custom gun, there is also the possibility that the neck material is too thick for the chamber and turning may be required to allow the bullet to have a clean release.
 
I've been using a Broughton 1-8" 5R and my 6BR. I only use 105gr Bergers. It never liked the Lapua 105's.
It will group easily under .5 MOA if I do my part. I had a McLennan in 1-8.5" 6BR [no 5R] that never shot well from the start until I made it into a .243 Ackley then it shot great till burned out.
 
Yeah you bet. I've scrubbed it out with Wipeout,let it sit overnight and patched it out. No copper. I wish the weather was a little better so I could get to some more testing.
 
Could be a carbon ring or a scalled throat. I would try some JB bore paste if it still isn't shooting when you do.

My Crusader seem to hold their accuracy longer when I use KG-2 every 500 rds. or so.
 
Another trick that I should not even tell you guys is 1500 scotch bright.
After you have a fair number of rounds through the barrel it starts to develop micro cracks that can cause accuracy degradation.
If you oil up a small patch of 1500 scotch bright and short stroke it from back to front you will find it will bite hard the first time through.
That means you are doing good. After a few stokes it will free up and then slide well then just push it out and follow up with a nice cleaning, Maybe with Iosso or JB bore paste.
1500 scotch bright is so fine that it will not damage your rifling, but don't make a career out of it.
 
Well finally got out to the range the other day. Shot a bunch more loads to see if I had missed something. Fired about 40rds on 5 shot groups. Shot some loads with 36.3
gr of 8208 XBR and got a couple of decent groups at 200m. First one had three piled up on each other and the other two piled together about 1/4 in away. Measured .75 inch. I probably moved causing the split while firing the string so I was pretty happy with that. Last couple of groups seemed to all of a sudden come together. Shot another group with the same load and got 4 shots into .25 of an inch with the last one landing far enough away to open it up to .63ish. The pull was all me. Last group was 40.5gr of H4350 and those ones too went into about .6.
So hopefully I'm back on track. Ive brewed up more to go back and verify my findings. Love to shoot them at 300m Tomochan next time your heading out.
 
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