6 SLR ES/SD help

[montana_native]

I've been struggling with the ES/SD on a recently chambered 6 SLR. The ES over a 5 shot string can vary by up to 70 fps. I don't recall having a string result in less than 30 fps. All velocities have been measure with a Labradar.

I am shooting non-sorted 115 DTACs. I am using a charge of H1000 between 45 and 47 grains. The bullet is being jumped about 0.030". Barrel is 26" long and is a Bartlein LV 7.5 twist.

This is all with annealed Wincester brand brass on a Benchsource, necks have been inside reamed with a Wilson trimmer.

I am using CCI200s and am wondering if I am getting inadequate ignition with this amount of powder. Would magnums be appropriate?

Are there any obvious red flags that may be contributing to this issue? Accuracy has been good. It's just the ES that has me concerned.

Thanks.

 

[jlow]

Inside neck reaming can lead to some pretty scratched up necks (inside)... A how even was your seating force?

 

[montana_native]

Seating force seems relative consistent with the occasional outlier. I usually set those aside.

I had this issue before reaming necks too and figured it was due to the donuts.

 

[eric32]

Inside reaming is horrible on the necks and bullet release. I would do a experiment with outsidr neck turned brass vs inside neck reamed.

I think the outside neck turned brass will yield a ES 10 to 15 FPS

 

[Capt. Oblivious]

Im using the equivalent of H4831 (45.8gr) behind a 105gr Molyd Amax with a federal 215 primer in my SLR. Brass (Winchester) is H20 sorted to within 0.4gr and necks walls are turned down to 0.0135" (have a tight chamber), then sized in a full length bushing Die, neck tension with a 105amax and 97gr VLD is 1.5thou. The last 5 shot string I fired over a Magneto speed had a ES off 3fps for the 5 shots, High of 3002 and low of 2999fps. I would also give neck turning the outsides a go if its was me, my Win brass has relativity consistent internal dimensions/capacity but the neck wall thickness is a completely different story

 

[Auto-X Fil]

Try a few different primers. BR-2, 210M, 215M, 9 1/2. I bet it's ignition.

Did you remove the burr from the inside of the flash hole? Winchester brass can be pretty rough.

 

[jlow]

Seating force seems relative consistent with the occasional outlier. I usually set those aside.

I had this issue before reaming necks too and figured it was due to the donuts.

You had not told us the number of firing this brass has gone through or the possibility of a donut. However, there is also no reason to not believe that your previous problem with ES was with the donut and your current problem is with the inside neck reaming - they both can cause the problem you are seeing.

 

[Rtheurer]

Check what Jlow Points out and then go get a Magnum Primer for that full case of H1000. H4831 Sc in the 43.5gr area seems to be fine with normal non magnum primers. H1000 and 7828 at 47gr ish seem to respond to the Magnum Primers very well.

 

[Dgd6mm]

When I first started shooting my 6mm Competition Match back in '07 I used CCI BR-2 primers. I seen similar es on the chronograph. I tried WLR and it got better, except for the fact that I had a run of those primers that had blowouts in the cup, which ended up with a burnt boltface. I then went to Tula LRM primers and it turned out great. This is with running 48.7-51.0 grains of H1000. I believe it is more of a primer issue then inside neck reaming. I can send you a picture of my last 10 shot group (215 yards) out of a barrel with over 5100 rounds down it. The brass was inside neck reamed, over 20 firings, never appealed. It measured barely over an inch, I fired off the wood bench, Harris bipod, squeeze bag, and fast like I was running in a Tac match, under 40 seconds. This rant has nothing do do with the barrel round count, and all to do with brass condition, powder, and primer, especially the last two.

Don Dunlap

 

[jlow]

Check what Jlow Points out and then go get a Magnum Primer for that full case of H1000. H4831 Sc in the 43.5gr area seems to be fine with normal non magnum primers. H1000 and 7828 at 47gr ish seem to respond to the Magnum Primers very well.

Agreed! I've only concentrated on "neck tension" but primers does make a significant difference.

 

[XTR]

I would suspect ignition before something in the front of the bullet if you have reasonable reloading skills.

1. Try a different primer(s). Probably want to use a magnum with the slow powders you will try to use in this case.
   
2. Try a different powder. I found H1000 to be too slow for the 6SLR when I tested it with 105s, with 115s you may be in a good place, but I think it's close to not being able to get to the pressure it wants. .
3. How old is the rifle? If it's over 3 yrs look at replacing the firing pin spring.

 

[montana_native]

Thanks for the input so far. I'll try some different primers and report back. I might also go from a 272 bushing to a 271. Neck tension is pretty light with the 272.

The rifle is built on a new Stiller TAC30 action. The primer strike looks to be substantial.

The flash holes were deburred.

Thanks again.

 

[eric32]

post up some pictures of the groups and stop inside neck reaming and outside turn the brass

 

[MOShooter]

I had the same problem with my 6slr. I tried 3 powders and a couple different primers, no mag. I think it was a brass problem. I was using Hornady. But after checking some new Win brass I abandoned the SLR. With the same loading method my 6.5x47 runs an ES of under 10. I have similar results with my 308. Lapua brass seems to be the key.

 

[jlow]

I had the same problem with my 6slr. I tried 3 powders and a couple different primers, no mag. I think it was a brass problem. I was using Hornady. But after checking some new Win brass I abandoned the SLR. With the same loading method my 6.5x47 runs an ES of under 10. I have similar results with my 308. Lapua brass seems to be the key.

I could be the brass. I've seen some significant differences in brass weight using Win .308 brass. OP should weight his brass to see what the weight spread is.

 

[Rtheurer]

its not the brass, try a magnum primer.... just try it. What is it going to hurt to try it?

 

[Frankr]

What kind of scale are you using to weigh your powder. ? I had a issue once with my scale was off...5gr or so and not always.. I load on a GEM PRO 250 now and I guess I have to trust it..But I have seen a scale be off .3 to .5 gr load to load..

 

[MOShooter]

its not the brass, try a magnum primer.... just try it. What is it going to hurt to try it?

I fully believe my issue was brass. I could feel a difference in seating pressure. My seating depth would vary .0010 from round to round. It also ran a 4gn weight spread in 200 pieces from the same lot.

 

[Rtheurer]

I fully believe my issue was brass. I could feel a difference in seating pressure. My seating depth would vary .0010 from round to round. It also ran a 4gn weight spread in 200 pieces from the same lot.

Yes sir that is not good.. I concur. To the OP. Might want to try a Magnum primer.

 

[jlow]

It could be a number of things, but coming from a job that involves mostly troubleshooting, never underestimate the possibility that it could be more than one thing....