6.5 SLR Range Report

[Hengehold]

2 Oct 2018:
After Fireforming some brass I ran a velocity ladder for a 6.5SLR (long throat). A copy of the LR chamber print is at the following link http://www.6mmar.com/65_SuperLR.php . I fired 2 rds at each powder weight. Used a Labradar for the test. Ambient temperature was 80 degF.

For those interested in this cartridge, here are the results.

32" 1-8 Krieger light palma barrel

H4831SC
140gr Nostler RDF, naked, .020 Jam
Wolf primer
Peterson 260 brass fireformed. (necks turned. factory neck thickness .015. Necks have been turned to .013. )

41.5- 2533, 2549
42.0- 2594
42.5- 2599, 2599
43.0-2643, 2636
43.5-2691, 2663
44.0- 2712, 2735
44.5- 2750, 2772
45.0-2777, 2781 bolt lift slightly stiff
45.5- 2815, 2799 bolt lift slightly stiff
46.0- 2831, 2855 bolt lift slightly stiff

On the last 3 charges the bolt lifted harder than if it were an empty chamber but I could still open the bolt with 2 fingers. I would say that 44.5 is the top end of the safe zone in this barrel with H4831SC. I did not see a flattening of velocity enough that may indicate a node for follow on group testing. I am going to move to a faster powder such as H4350 or IMR4350.

9 Oct 2018:
No sticky bolt was felt with any of the H4350 loads. Some minor smear marks on case heads in the upper end of the powder charges was noticed.

H4350
140gr Nostler RDF, naked, .020 Jam
Wolf primer
Peterson 260 brass fireformed. (necks turned. factory neck thickness .015. Necks have been turned to .013. )
*85 Degree F. ambient Temp

39.0- 2657, 2682
39.5- 2715, 2713
40.0- 2715, 2745
40.5- 2751, 2778
41.0- 2777
41.5- 2797, 2801
42.0- 2838, 2847
42.5- 2890
43.0- 2901, 2922
43.5- 2961

10 Oct 2018:
I have a bunch of N150 on hand and since N150 and H4350 are close on the relative burn rate charts that are available on the internet, I decided to give N150 a try.Obviously, there is a bit of a difference between H4350 and N150 after looking at the results. No sticky bolt lift was felt with any of the N150 loads.

VV N150
140gr Hybrid, naked, .015 Jump
Wolf primer
Peterson 260 brass fireformed. (necks turned. factory neck thickness .015. Necks have been turned to .013. )
*85 Degree F. ambient Temp

32.0- 2447
32.5- 2457, 2420
33.0- 2483, 2473
33.5- 2519, 2513
34.0- 2537, 2547
34.5- 2598
35.0- 2593, 2591
35.5- 2635, 2613
36.0- 2650 *Max load according to Vihtavouri.com
36.5- 2697, 2703
37.0- 2724, 2728
37.5- 2762, 2750
38.0- 2786

 

[XTR]

What is the difference in case capacity between your SLR cases and your 260 cases?

Just a data point. I have a 6SLR and the conventional wisdom is/was that you lose way more capacity than my data shows. I think the differece in water capacity between my 6SLR and a 243 was in the range of .2gr of water between my fired SLR cases and my new 243 cases (i.e., not very much).

 

[Hengehold]

What is the difference in case capacity between your SLR cases and your 260 cases?

Just a data point. I have a 6SLR and the conventional wisdom is/was that you lose way more capacity than my data shows. I think the differece in water capacity between my 6SLR and a 243 was in the range of .2gr of water between my fired SLR cases and my new 243 cases (i.e., not very much).

I have No idea on the change in case capacity.

 

[D.Stone]

Those numbers kind of suck.

I am able to safely get 2900fps out of a 260 Remington with 140gr bullets and H4350. My barrel is only 26 inches.

Even my Creedmoor is at 2860fps and that's a mild load that works even when the ammo is soaking wet.

 

[Hengehold]

Those numbers kind of suck.

I am able to safely get 2900fps out of a 260 Remington with 140gr bullets and H4350. My barrel is only 26 inches.

Even my Creedmoor is at 2860fps and that's a mild load that works even when the ammo is soaking wet.

Agreed. I was expecting to get 2800 FPS very easily, even with the slower powder such as H4831sc. In this case, 2800 seemed to be in the questionable zone of pressure.

-T

 

[Laurie]

I have a 6SLR and the conventional wisdom is/was that you lose way more capacity than my data shows. I think the differece in water capacity between my 6SLR and a 243 was in the range of .2gr of water between my fired SLR cases and my new 243 cases (i.e., not very much).

........... but the valid comparison is between fireformed pieces of brass. Not an option I know with a 'wildcat', but the capacity difference will increase over fireformed v new. (The other option of course is to compare the new case capacities in out of the box v reformed in an SLR die - not nearly as good as using fireformed brass. but at least both measurements are taken on the same basis.)

(Nice cartridge, the 6SLR. I bought one with a well-used barrel so my use was limited, but I retained the dies after rebarrelling to 6BR as I have a yen to do another SLR some time in the future.)

 

[Laurie]

Peterson 260 brass fireformed

Peterson 260 Rem is a heavy make. My fireformed (standard 260) Peterson cases hold 53.9gn water compared to 55.6gn for Remington. That's enough to lose you some velocity on maximum safe pressure - not huge amounts, but maybe 30 fps or so, then add in a bit more capacity loss through the reforming to SLR.

 

[Capt. Oblivious]

Is it a new barrel? Fill that case with VihtaV N5 series, N550 or N560 should get you up where you want to be without to much trouble

 

[Hengehold]

Is it a new barrel? Fill that case with VihtaV N5 series, N550 or N560 should get you up where you want to be without to much trouble

Yes barrel is brand new. I have 4 lbs of VV N560 but on the Lapua burn rate comparison chart N560 and H4831SC appear to be about the same, so I didn't think that would produce different results. I will give it a try and see what happens. In fact, I have N560, N150, & IMR 4350. I will run a velocity ladder on all three and compare that to the velocities that I get from H4350. Unfortunately, I only have about 1/2 pound of H4350 on hand so that is just enough to get a baseline for comparison numbers. My impression is that H4350 is probably the best burn rate to go with and I am trying to use powders that I have in my inventory that are close to the H4350 burn rate.

As an aside, I am under the impression that the N500 series powders have a reputation for shortening barrel life due to the Nitroglycerine that is in the powder. However, VV website states that it produces greater velocities with NO affect on the barrel life.

I don't want to get stuck using H4350 because it is hard to find in stores these days. Thanks a lot Hornady/Creedmoor :-(

-T

 

[Prose]

Did you turn necks after forming from Peterson cases?

 

[XTR]

I'm going to guess that N150 is too fast. I run it in my 308. I don't get results that indicate that it's as slow as the burn rate charts indicate. I have a 200.20x load that isn't significantly different from Varget loads for the same speed in F-TR rifles.


Be careful with velocity claims from bulletin boards. When I started with F-TR I discovered that I had either the slowest 30" barrel ever made by Kreiger, because guys with 24" tubes claimed to be getting the same velocities that I was, or I had a really slow chrono [/sarcasm]

Nosler says you are pretty spot on for their loading with 140 class bullets

As does Barnes, and Berger... you get the idea. Yea, you can probably get them to run faster than the listed numbers, but not by much unless you are seating them longer than mag length. Hanging them out the case gives you more volume to play with. The 6.5SLR should be pretty close to identical to the load data for the 260Rem parent case (it is in the 6SLR version)

 

[Hengehold]

Did you turn necks after forming from Peterson cases?

Yes, I had to turn necks and ream out doughnut. Factory neck thicknesses were .015. I had to turn them to .013. Nk dia on the JGS reamer made to Whitley's specs is .298. I origionally turned necks to .014 and the fired case mouth after fireforming would not allow a bullet to enter the case prior to resizing. This suggested that the clearance between case neck and chamber wall was too close.

 

[Prose]

Do you have a really slow lot of powder? Has the lot your using shot quickly in other cartridges?

 

[Laurie]

Yes barrel is brand new. I have 4 lbs of VV N560 but on the Lapua burn rate comparison chart N560 and H4831SC appear to be about the same, so I didn't think that would produce different results. I will give it a try and see what happens.

Remember that most stainless match barrels produce higher pressures and MVs after a couple of hundred rounds down them, so initially disappointing velocities aren't necessarily a case for too much concern. (Conversely, working up to a maximum pressure load very quickly on a new barrel can see blown primers and other pressure problems later appear with that load.)

Adding nitroglycerin to base N100 series powders to get an equivalent N500 series product changes their behaviours significantly and burning rate charts are often very misleading here. In practice, N560 usually behaves as a significantly slower burner than H4831 irrespective of their relative position in such charts. (IME, its single-based N160 relative usually works out in the other direction being quicker than either IMR or H4831 and in some cartridges / loads is closer to the 4350s in its behaviour.)

N560 will give significantly higher MVs than the 4831s in the 260 and its variants if loaded up to maximum pressures which usually see compressed loads too. That's because it's a high-energy powder, the addition of nitroglycerin making it denser too through changes in the kernels' molecular structure. Put these two factors together and you can pack more energy into a limited size case - and that applies to 260 before bumping the shoulder back. As to barrel life, that depends on the load and resulting pressure. These high-energy powders can match or slightly exceed H4831 velocities but at significantly lower pressure. It shouldn't increase barrel life when loaded like this, may even improve it if Viht's additives to reduce flame temperatures work as the company claims. But, go that extra 2gn or thereabouts higher to get the maximum velocity on offer at full pressures and you will reduce barrel life significantly.

 

[1lnbrdg]

I'm not a 260 shooter myself but close friend is. Seems like a lot of the nearby 260 shooters are moving to IMR 4350. They are finding it to be very accurate over all the other powders.

 

[Hengehold]

I'm going to guess that N150 is too fast. I run it in my 308. I don't get results that indicate that it's as slow as the burn rate charts indicate. I have a 200.20x load that isn't significantly different from Varget loads for the same speed in F-TR rifles.


Be careful with velocity claims from bulletin boards. When I started with F-TR I discovered that I had either the slowest 30" barrel ever made by Kreiger, because guys with 24" tubes claimed to be getting the same velocities that I was, or I had a really slow chrono [/sarcasm]

Nosler says you are pretty spot on for their loading with 140 class bullets

As does Barnes, and Berger... you get the idea. Yea, you can probably get them to run faster than the listed numbers, but not by much unless you are seating them longer than mag length. Hanging them out the case gives you more volume to play with. The 6.5SLR should be pretty close to identical to the load data for the 260Rem parent case (it is in the 6SLR version)

Thanks for the info. When looking at the Lapua burn rate comparison chart, it looks like N150 and H4350 are similar. However, when I referenced the online loading manuals at VV and Hodgton for the 260 Rem I found very different load recommendations.

VV N150: Start load=31.0, Max=36.5
H4350: Start load=39.0, Max=43.0

There is a lot more variation there than I expected. The results of the ladder test will be interesting.

-T

 

[Hengehold]

I'm not a 260 shooter myself but close friend is. Seems like a lot of the nearby 260 shooters are moving to IMR 4350. They are finding it to be very accurate over all the other powders.

I am glad to hear that. Thanks for sharing, it is definitely on my list of powders to try. I am using IMR 4350 in my 6xc at the moment but decided to do it begrudgingly. I was reluctant to use it since it is not marketed as being temperature insensitive where some of the other powder options are marketed as being less sensitive to temperature. Obviously, one will want to stay away from working up loads for different temperatures. I have not used the IMR Enduron powders. perhaps this will become an excuse to try them out if what I have does not workout.

-T

 

[Hengehold]

Remember that most stainless match barrels produce higher pressures and MVs after a couple of hundred rounds down them, so initially disappointing velocities aren't necessarily a case for too much concern. (Conversely, working up to a maximum pressure load very quickly on a new barrel can see blown primers and other pressure problems later appear with that load.)

Adding nitroglycerin to base N100 series powders to get an equivalent N500 series product changes their behaviours significantly and burning rate charts are often very misleading here. In practice, N560 usually behaves as a significantly slower burner than H4831 irrespective of their relative position in such charts. (IME, its single-based N160 relative usually works out in the other direction being quicker than either IMR or H4831 and in some cartridges / loads is closer to the 4350s in its behaviour.)

N560 will give significantly higher MVs than the 4831s in the 260 and its variants if loaded up to maximum pressures which usually see compressed loads too. That's because it's a high-energy powder, the addition of nitroglycerin making it denser too through changes in the kernels' molecular structure. Put these two factors together and you can pack more energy into a limited size case - and that applies to 260 before bumping the shoulder back. As to barrel life, that depends on the load and resulting pressure. These high-energy powders can match or slightly exceed H4831 velocities but at significantly lower pressure. It shouldn't increase barrel life when loaded like this, may even improve it if Viht's additives to reduce flame temperatures work as the company claims. But, go that extra 2gn or thereabouts higher to get the maximum velocity on offer at full pressures and you will reduce barrel life significantly.

Thank you for the detailed response.
-T

 

[Laurie]

I'm going to guess that N150 is too fast. I run it in my 308. I don't get results that indicate that it's as slow as the burn rate charts indicate. I have a 200.20x load that isn't significantly different from Varget loads for the same speed in F-TR rifles.

That's my experience of N150. It is not an equivalent to the 4350s as shown in most burning rate charts. In my last (standard freebore) 260 barrel, I got good results and MVs from the 123gn Lapua Scenar with this powder, but I wore the barrel out a lot faster than expected, so believe I was running higher pressures than I thought. 260 + N150 even with 120s-130s is rather 'peaky' IME - go past a certain point and a small charge weight increase moves from no pressure signs to blowing primers in Lapua brass.

Ideally, I'd run small primer / flash-hole brass in the 260 as I do in 308 and 7-08, but my rifle, an FN SPR (= Win 70 action), has a fat firing pin tip and blanks SR primers at low pressures. This barrel has a long-freebore chamber to let me run 140s at decent MVs (2.95-2.99" COALs), but I've yet to get a feel for optimum powders despite what QuickLOAD suggests. Kicking off with the 140 Berger BT and 142 SMK, I found Viht N160 performing around where expected, but nothing to note MV wise; N550 produced higher pressures / MVs than QL calculated and looks to have potential, N560 and Reload Swiss RS70 (double-based EI grade shown on burn charts as slower than H4831 and equivalent to Re22, Norma MRP and Viht N165 both produced MVs a full 100 fps down on what QuickLOAD predicted. However with less than 100 rounds down the barrel, I'm content to see the round-count build more before drawing too many conclusions here. The rifle action generally doesn't group well at maximum or near maximum pressures so I'll be happy if I can get 2,800 from these bullets (28-inch barrel), good accuracy and consistent performance on every outing.

 

[RustyPin]

I'm curious what the Capacity would be from Fire Formed Winchester Brass. Maybe 60gn err slightly less...?