6.5cm powder.

[NamibHunter]

IMR4350 is definitely temperature sensitive.

Yes IMR4350 is very much temperature sensitive. At the time when H4350 became unavailable, this powder was my fallback. It works ok if you develop winter and summer loads, but not my favorite powder. What counts for it is lower price and very good availability, but H4350 has much better temp stability.

[BTW: Loads were not identical as burn rate is slightly different. Some variation from batch to batch as well.]

 

[NamibHunter]

I clean every 100-200 rounds. I do get a carbon ring, but it cleans out with Bore Tech Carbon Remover, a nylon brush and short cleaning rod without much trouble. YMMV. For the rest of the barrel I just run 3 wet patches, followed by dry patches and repeat once. The Teslong borescope is great for checking for that carbon ring and seeing when it is cleaned up. The temp sensitivity shown in 4DOF for RL16 is .11 fps per degree. I haven’t based my cleaning frequency on any accuracy changes, just on convenience. I think if you stay ahead of the carbon buildup it is easier to deal with.... just my theory.

Thanks much, good to know. I think i will try RL-16. Looks like one can deal with the carbon fouling if you follow a good cleaning regimen.

Btw: The new Hornady reloading data posted on their web site for the 135 gn A-tip Match bullet lists RL-16 as the fastest option at 2850 fps, then RL-17 at 2825 and lower down the list is H4350 at 2775 fps. Seems to confirm that RL-16 outperforms RL-17 in the speed stakes, for the 135 to 142 gn projectiles.

 

[NamibHunter]

Does anybody know what powder works best with the heavy 150 gn Sierra SMK and 156 gn Berger EOL projectiles, or the new Hornady 153 A-tip?

 

[captainmorgan460]

Ive had better results with rl16 than h4350 by far.

 

[supercorndogs]

Same for me: RL-17 shot groups in the 0.25” to 0.5” range from a 26” factory Savage barrel at 2850 fps, and could go even faster before pressure signs showed up. At least a 150 fps faster than H4350 before half moon and full moon ejector marks appeared. Have been told that is wears our your barrel faster, but not sure about that. Also: Very temperature sensitive.

Most accurate results came from H4350: Best 3 shot group ever was 0.08”, 0.15” to 0.25” was typical at 100 yards.

Replaced the 26” factory barrel with a 30” Shilen Select Match barrel (intent was to experiment with a longer barrel and see what speeds could be achieved). H4350 did not gain any speed! Big surprise. I bet a 28” barrel would have shown a speed increase and that it is losing speed after that. Would be interesting to hear what others have found with 27 or 28” barrels. Accuracy was best with Berger 140 Hybrids and 140 ELD-M.

RL-17 could achieve incredible speeds from the long 30” barrel: At 60 degrees F ambient temp the 140 gn ELD-M achieved 2920 fps. Around 180 to 200 fps faster than the max load for the old 26” barrel. The load was not safe for peak summer temps (105 deg F). Peak summer speed was around 2880 fps. Needed a winter and summer load.

The addition of the 30” barrel combined with RL-17 effectively changed a 6.5CM into a 6.5x284, but with far better barrel life. I got 2,800 from the fist barrel. Of course, the gun is now heavy, hard to transport (2.5” long Vais brake has to come off before it can fit into the bag), also very front heavy and not at all practical for a walk and stalk hunt. But it has shot 2”-3” groups at 600 on calm days using RL-17 (and Superformance, which is also very temperature sensitive).

Would not recommend Superformance, gave up on it after a case was badly mangled shooting on a hot day.

Moral of the story is: RL-17 works very well in short and especially long barrels, as long as you develop a winter and summer load. Pros and cons.

But H4350 gave the smallest groups. Most people who own a 6.5CM and reload use H4350 and so it is in short supply and often overpriced.

It takes way more than a 30" barrel to start slowing a down a 6.5 Creed.

 

[NamibHunter]

It takes way more than a 30" barrel to start slowing a down a 6.5 Creed.

Could be.

I was trying to say that H4350 is not ideal if you want to exploit a really long barrel. There are alternative powders that do much better. I bet that if i cut off one inch from the Shilen barrel that MV will go up, if H4350 is used)... maybe one day i will try that.

My guess is that beyond 28” you are not benefiting enough to bother with additional barrel length in a 6.5 Creedmoor. The disadvantages start to outweigh the advantages. My next barrel will not be 30” long, probably 28” or 27”, and a lighter profile.

In a 6.5 PRC, i bet a 32” barrel will achieve higher MV than a 30”, but that is just gut feel. Maybe somebody has tried that?

Some barrels are also slightly tighter than others... so barrel brand might affect the result.

 

[supercorndogs]

Could be.

I was trying to say that H4350 is not ideal if you want to exploit a really long barrel. There are alternative powders that do much better. I bet that if i cut off one inch from the Shilen barrel that MV will go up, if H4350 is used)... maybe one day i will try that.

My guess is that beyond 28” you are not benefiting enough to bother with additional barrel length in a 6.5 Creedmoor. The disadvantages start to outweigh the advantages. My next barrel will not be 30” long, probably 28” or 27”, and a lighter profile.

In a 6.5 PRC, i bet a 32” barrel will achieve higher MV than a 30”, but that is just gut feel. Maybe somebody has tried that?

Some barrels are also slightly tighter than others... so barrel brand might affect the result.

A 30 inch barrel is not slowing down a 6.5 creed with H4350.

 

[quest450]

What is the best powder for 6.5cm? I'm in AZ so I need good temperature stability. I'm running a Remington 700 with 22" barrel. 140gn BTHP bullets and Hornady brass. I've got 500 once fired cases. Thank you for your time and help!

I'm in South FL so 95F is the norm
My 26" Bartlein HVV barrel likes RL-16
2810fps with 41.70gr of RL-16, 147gr Hornady ELD M, CCI BR-4

 

[NamibHunter]

A 30 inch barrel is not slowing down a 6.5 creed with H4350.

Thinking about this some more, you could well be right. A slow barrel can be 50 fps slower than an average barrel, and a fast barrel like a Bartlein 5R can be 50 fps faster than average. So maybe there is potential for a 100 fps delta?

At what point does barrel length slow down a bullet: Have read in the reloading books that the magic number is around 42”. Is that true?

My basis for comparison is likely somewhat flawed. Had a 26” Savage factory barrel (that shot remarkably well) with H4350, and it died when it reached 2,800 rounds down the tube. Rough interior and lots of copper fouling. Cleaned it around every 200 rounds (chose to believe the copper equilibrium theory...). Replaced it with a Shilen Match Select barrel (advertised as air gauged to within i think 0.2 thousands of an inch). Mirror finish on the inside and almost no copper fouling. Shot the same ammo loaded with H4350, through both barrels, and speed was almost the same. The 30” barrel was maybe 10 fps faster. That was a big surprise (and a major disappointment!). Do you think the Shilen barrel could be that much slower than the factory Savage barrel? The extra 4” should have been worth somewhere between 80 and 100 fps. Does anybody have experience with 6.5 CM barrels that are longer than 28”, what speed are you getting with H4350 or RL-16? What powders work best? [i was hoping to get the 150 SMK to 3,000 fps, but got a node around 2920 fps, so stopped pushing it). Shot ok, but not great.]

 

[XLR308]

Does anybody know what powder works best with the heavy 150 gn Sierra SMK and 156 gn Berger EOL projectiles, or the new Hornady 153 A-tip?

The only one I have tried so far is H4350 with a moderate charge weight just to do a quick seating depth test to see how they would behave jumped.
At .015" off the lands the average velocity was 2680fps from a 23" Bartlien 1-7.5" twist.
In my rifle I don't see any indications that the 150smk couldn't be easily run above 2700 even from the relatively short 23" barrel.
This was also done with new Lapua brass.

 

[Hundo]

H4350 and RL16 are the two best, when using a 140 gr. Their are a few others, but start with either
one of these first. Very close in measuring weight. The RL16 seems to produce a little more fps
before you hit max.

Ditto on those 2. I get a little more (less than 30 fps) velocity from RL16, but a little better accuracy (both loads are sub-moa) from H4350. May favorite load is 42.0gr of H4350 pushing a 143gr ELDX 2683fps from a 20 inch barrel. Hornady brass and CCI primers. In theory, RL16 is less sensitive to temp change although the H4350 is certainly not bad.

 

[NamibHunter]

Just trying to learn: Is the general experience and consensus opinion that RL-16 gives faster speeds than H4350 (and how much, given bullet weight and barrel length)?

And does RL-16 generally produce slower speeds than RL-17, or about the same? The Hornady online reloading manual does not always show all three. They often show Superformance, but i have given up on it.

[Not generally keen on achieving rediculous speeds, just trying to learn.]

 

[JWHanks]

I haven't seen it mentioned yet but I use IMR 4451 with success. I was using H4350 previously but the 4451 has been more consistent in my 26" benchmark barrel and the 140 ELD-M. I have not tried any RL16 but a friend of mine really likes it in his 6XC.

 

[Kalashnikov]

Here in South Africa quite a few guys use Vihtavuouri N550 with great success and more speed. Havent tried it yet myself

 

[NamibHunter]

Here in South Africa quite a few guys use Vihtavuouri N550 with great success and more speed. Havent tried it yet myself

Could be a viable option too.

Had a look at the VV web site: It shows N550 pushing 140 gn projectiles to 2680 fps or so, in a 25.5” barrel. Presume this is a rather conservative load?

Anybody who has tried it?