6SLR Project

[Whisky Tahoe Foxtrot]

I have been breaking in a 6SLR and learning a few things as I go. The rifle is a 40X BR action with a brux barrel in a bedded Richards Microfit laminated stock.

I only have 73 rounds down the barrel so far and expect it will take a few more rounds before I can get the best accuracy.

I'm migrating fired 243 brass from the original 40X 243 barrel into 6SLR with a match chamber.

I ran into brass extraction issues with "fat" base brass which I remedied by using a .308 small base die which took the brass diameter above the extractor ring from .472 to .468-.469.

Running fired .243 brass through the SB die before 6SLR sizing reduced the work required to reshape the 6SLR neck. I should have known this prior to loading those first few cases but I know it now.

Lapua brass needs a fair amount of neck prep.
It is what I had so I worked through it using these steps.

Anneal case using .243 setting
Base sizing (RCBS .308 SB die)
6SLR Full length sizing (Whidden non Bushing 6SLR die)
Trim Case (Forster with 3in1 tool and power adapter) (Yes all of you with a Giraud are too cool for school)
Expand Necks (21st Century 6mm Expander)
Turn Necks on Lathe (21st Century full lathe with 6mm Arbor & power adapter)
Ready for tumbling, priming, loading, seating, and shooting

After initial testing, I'm seeing stringing which is common with slower burning powders and light neck tension. To increase neck tension with my current setup, I need a few different mandrel sizes that push the neck out less. Some Reloaders who use mandrels actually use Pin Gauges but I haven't found any dies that hold pin gauges yet. Would love to get more info on that.

Alternatively, I can replace the non bushing die with a bushing based die and get neck tension adjustment that way. I felt the initial sizing operation from 243 to 6SLR would be best in a non bushing die but after that initial prep a bushing based die could be evaluated. I'm aware that adjusting neck tension is a well debated topic. I'll keep an open mind while testing these methods.

In addition to tackling Neck Tension I have to backup and work through powers, bullets, and seating depth choices.

Powders: N160, 4831SC, and H4350 already on hand
Bullets: SMK 107s, SMK 110s, and DTACs followed by trying all the 105s and 108 Bergers

 

[R.Olds]

Very nice....thanks for sharing.

I just picked up some Berger 108's to try, I have been pretty happy with the Berger 115's touch to +.005 and a 43.5 shot of 4831sc.
I need to lengthen my throat to run the 115 Dtac's, the Dtac boat tail joint is .035 below my case neck, they just dont seem to shoot well like that.

 

[dbduff]

I have been breaking in a 6SLR and learning a few things as I go. The rifle is a 40X BR action with a brux barrel in a bedded Richards Microfit laminated stock.

I only have 73 rounds down the barrel so far and expect it will take a few more rounds before I can get the best accuracy.

I'm migrating fired 243 brass from the original 40X 243 barrel into 6SLR with a match chamber.

I ran into brass extraction issues with "fat" base brass which I remedied by using a .308 small base die which took the brass diameter above the extractor ring from .472 to .468-.469.

Running fired .243 brass through the SB die before 6SLR sizing reduced the work required to reshape the 6SLR neck. I should have known this prior to loading those first few cases but I know it now.

Lapua brass needs a fair amount of neck prep.
It is what I had so I worked through it using these steps.

Anneal case using .243 setting
Base sizing (RCBS .308 SB die)
6SLR Full length sizing (Whidden non Bushing 6SLR die)
Trim Case (Forster with 3in1 tool and power adapter) (Yes all of you with a Giraud are too cool for school)
Expand Necks (21st Century 6mm Expander)
Turn Necks on Lathe (21st Century full lathe with 6mm Arbor & power adapter)
Ready for tumbling, priming, loading, seating, and shooting

After initial testing, I'm seeing stringing which is common with slower burning powders and light neck tension. To increase neck tension with my current setup, I need a few different mandrel sizes that push the neck out less. Some Reloaders who use mandrels actually use Pin Gauges but I haven't found any dies that hold pin gauges yet. Would love to get more info on that.

Alternatively, I can replace the non bushing die with a bushing based die and get neck tension adjustment that way. I felt the initial sizing operation from 243 to 6SLR would be best in a non bushing die but after that initial prep a bushing based die could be evaluated. I'm aware that adjusting neck tension is a well debated topic. I'll keep an open mind while testing these methods.

In addition to tackling Neck Tension I have to backup and work through powers, bullets, and seating depth choices.

Powders: N160, 4831SC, and H4350 already on hand
Bullets: SMK 107s, SMK 110s, and DTACs followed by trying all the 105s and 108 Bergers


View attachment 1142995 View attachment 1142996 View attachment 1142997

Using Peterson srp243 brass. Finding that tuning at 300 isn't necessarily easy. Shooting 105 and 108. Re 16 can give good groups but if above 80degrees can give real heavybolt lift. Not so at 65 degrees. SLR is awork in progress, promising but frustrating as well. Interested in your victories and not victories. Be glad to share what works on my end.
D

 

[Whisky Tahoe Foxtrot]

Very nice....thanks for sharing.

I just picked up some Berger 108's to try, I have been pretty happy with the Berger 115's touch to +.005 and a 43.5 shot of 4831sc.
I need to lengthen my throat to run the 115 Dtac's, the Dtac boat tail joint is .035 below my case neck, they just dont seem to shoot well like that.

Yes the Berger 115s should also be considered. Regarding your experience with DTAC, I didn't have great results when I was shooting .243 so I won't be too surprised if they don't like this barrel either. Several of the shooters who share have mentioned that seating above the donut is important. When you can't do that as you clearly can't, then make sure you don't have a donut. Drag a straightened paper clip in the neck and see what you "feel". Thanks for the info on Berger 115s

 

[Whisky Tahoe Foxtrot]

Using Peterson srp243 brass. Finding that tuning at 300 isn't necessarily easy. Shooting 105 and 108. Re 16 can give good groups but if above 80degrees can give real heavybolt lift. Not so at 65 degrees. SLR is awork in progress, promising but frustrating as well. Interested in your victories and not victories. Be glad to share what works on my end.
D

I share your issues with 300 yds. Now I shoot for group size at 100 then take my best bet/guess to 600 where my club has shotmarker scoring. I get quick feedback and it's great practice. While I tempted to jump in and start working up alot of bullet/powder combinations, I'll focus on my neck tension challenge for now on my current load 1st.

 

[R.Olds]

Yes the Berger 115s should also be considered. Regarding your experience with DTAC, I didn't have great results when I was shooting .243 so I won't be too surprised if they don't like this barrel either. Several of the shooters who share have mentioned that seating above the donut is important. When you can't do that as you clearly can't, then make sure you don't have a donut. Drag a straightened paper clip in the neck and see what you "feel". Thanks for the info on Berger 115s

My first batch of Dtac's were coated.....they seem to seat with a lot more force than naked bullets and were not very consistent on Ogive depths. I did just receive 100 of the naked Dtac's and will give them a try....who knows....LOL

 

[Capt. Oblivious]

Whisky grab a box of sako 243 brass and form them to SLR, I used lapua for a very long time but got tired of all the neck work.

The sakos only need a lite turn and they are ready to go and they seem very consistent. Im on my 4th firing of this 200 batch and they are still evey bit as good as the lapuas I used.

Im busy with 108gr ELDs with N160 in mine currently and should know how they shoot by next week.
This barrel has only seen HBNd 105gr HVLDs but im looking for something a bit less jump senisitive

The winds/rain are to much currently to shoot a ladder at 600 or 800y so im going to give Eric Cortinas 100y load development a go

 

[1lnbrdg]

4 years now on my SLR, YMMV.

I really like Win. LRP Brass, have to do some sorting but case capacity is GREAT!.

N-165 Powder seems to be the best for barrel life and cases last forever. Over 20 firings on some of them. Primers come out rounded still, ~3150 FPS with 105/107 wt bullets.

PTG reamer, ordered from them but didn't specify. They sent me a "Neck-Turn" tight neck reamer so I still have to turn all my brass. Will order another reamer sometime in the future non-neck turn for simplicity, shooting Sling with it's generous X/10-ring but current loads would hold ~1/4 min if my hold was that good. Thinning the necks down seems to be the downfall of the Winchester brass, where I loose the cases due to split necks. Yeah, go ahead and say I need to anneal but I usually do after every 3rd firing.

Trimming with a Gracey Trimmer using 6XC bushing.

 

[Bob3700]

Have been shooting the SLR since it first was developed. Have a 7.5 T 5R bartline that I had nitride hardened.

Best powder for me so far is H4831sc. 115 DTACS have been excellent for me as far as accuracy goes. The Berger 105 Hybreds are right there also. I shoot prone with sling and irons.

I purchased my JGS reamer that was spec'ed by Whitley for the 115 DTAC's. Winchester brass and no turn neck. I adjust my Winchester 243 brass to have a very light neck tension so that the weight of the press handle seats the bullets. Once seated there is just enough tension to keep bullets from being rotated by hand. I adjust the seater so that bullets are .030" long and closing the bolts seats the bullets the rest of the way. Using that method I don't have to chase a moving throat and seating depth is consistent.

The SLR has ballistics that are very close to the 6.5x284. I also believe that barrel life is just a bit better if you use slower powders. That said, it is also the reason I hardened the bbl. I would not expect 308 barrel life out of an SLR.

My rifle is an RPA Quadlite that has two bbl. fitted to it. One is the 5.4x284 and the other is the 243 SLR. Both are a lot of fun to shoot. Laser beams.

I would certainly give N160 and N165 a try with 110 SMKs. Those are some slick bullets that really retain velocity at mid and long ranges. Get those to shoot at 3150 fps and you will have something.

Bob

 

[R.Olds]

Have been shooting the SLR since it first was developed. Have a 7.5 T 5R bartline that I had nitride hardened.

Best powder for me so far is H4831sc. 115 DTACS have been excellent for me as far as accuracy goes. The Berger 105 Hybreds are right there also. I shoot prone with sling and irons.

I purchased my JGS reamer that was spec'ed by Whitley for the 115 DTAC's. Winchester brass and no turn neck. I adjust my Winchester 243 brass to have a very light neck tension so that the weight of the press handle seats the bullets. Once seated there is just enough tension to keep bullets from being rotated by hand. I adjust the seater so that bullets are .030" long and closing the bolts seats the bullets the rest of the way. Using that method I don't have to chase a moving throat and seating depth is consistent.

The SLR has ballistics that are very close to the 6.5x284. I also believe that barrel life is just a bit better if you use slower powders. That said, it is also the reason I hardened the bbl. I would not expect 308 barrel life out of an SLR.

My rifle is an RPA Quadlite that has two bbl. fitted to it. One is the 5.4x284 and the other is the 243 SLR. Both are a lot of fun to shoot. Laser beams.

I would certainly give N160 and N165 a try with 110 SMKs. Those are some slick bullets that really retain velocity at mid and long ranges. Get those to shoot at 3150 fps and you will have something.

Bob

If you dont mind, what powder charge are you running with your Dtacs, and are your Dtac's coated or naked....TIA

Rick

 

[Bob3700]

If you dont mind, what powder charge are you running with your Dtacs, and are your Dtac's coated or naked....TIA

Rick

I am just a bit north of 43 gr of H4831sc. My DTAC's are HBN coated.

 

[Whisky Tahoe Foxtrot]

FYI all Berger 109s are in the market and for some of us, self included, are another variable to test with.

Specifications
100ct Part #
24485

100ct MSRP
49.99

Caliber
6 mm

Bullet Weight
109 Grain

Product Line
Long Range Hybrid

G1 BC
0.568

G7 BC
0.292

G7 Form Factor
0.906

Minimum Twist (or faster)
1:8"

Ogive Style
Long Range Hybrid

Base Style
Boat Tail

Jacket
J4 Target Jacket

Sectional Density
0.264

Bullet Dia.
0.243

OAL
1.277

Base to Ogive
0.653

Nose Length
0.655

Bearing Surface
0.431

Boat Tail Length
0.168

 

[Ringostar]

Do you have a collet bullet puller? RCBS or Hornady. You can clamp mandrels (pin gauge) in the collet, to experiment with other neck tension. Then you can stay with your Whidden die for sizing.

 

[Capt. Oblivious]

Ill give the 109s a go as soon as I can find some but if my freebore was long enough id be shooting dtacs for sure, if these 108s dont do what I want I might have this throat opend up a bit . That bullet out of a big 6mm case is power

 

[Whisky Tahoe Foxtrot]

Do you have a collet bullet puller? RCBS or Hornady. You can clamp mandrels (pin gauge) in the collet, to experiment with other neck tension. Then you can stay with your Whidden die for sizing.

Great suggestion! I have a Forster puller with a collet for 6mm that should work.

 

[Whisky Tahoe Foxtrot]

Ill give the 109s a go as soon as I can find some but if my freebore was long enough id be shooting dtacs for sure, if these 108s dont do what I want I might have this throat opend up a bit . That bullet out of a big 6mm case is power

Grafs.com has them as a few others might as well

 

[Bob3700]

Grafs.com has them as a few others might as well

Check with McGee Stocks dot com. They are the largest Berger dealer n should have some in stock.

 

[Capt. Oblivious]

Grafs.com has them as a few others might as well

Thanks but im on the other side of the world so will have to wait till a boat makes its way over here

 

[McStocks]

Thanks, Bob!
Just a few notes on the SLR:
I conferred with Bob before I built ours and are very happy with it. We've only used the 105 Berger Hybrids and are getting over 3100. The 108s should be a good choice also, and we should be getting our shipment of 109s in any day, so we're anxious to try them!
Steve