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Vit double based powders


The Badger

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It’s an interesting topic and there is no right/wrong answer.

There is a commonly held view that the 5 series of powders cause excess wear. Take N550 for example - on VVs site you can see that it burns 7% ‘hotter’ than N160. Therefore it should have a greater impact on barrel wear than the single based line - you can’t change physics.

I’ve used N550 almost exclusively in my current .260 barrel and I’ve been keeping a log to measure the impact so you can make your own decision as to whether excess wear is acceptable or not for YOU. 

My barrel is a 26” Bartlein chambered by Alan Maughan (I think we all recognise the quality of his work). I do believe the quality of barrel and how well it’s chambered makes a difference but it’s nothing I can evidence. 

I’ve predominantly shot the 139gr Scenar at 2820 FPS and the 130gr Nosler RDF at 2920 FPS and I’m currently close to 2,000 rounds in. My OAL to ogive today is 2.305” using the same 139gr Scenar bullet that I tested the barrel with new at 2.240” so it has eroded. 

You can make your own decision as to whether that degree of erosion is acceptable or not but for me it’s absolutely fine for a few reasons. 

Firstly, I use a magazine and so even though I’ve chased the lands, I’m still comfortably inside mag length which is important to me. 

Secondly, accuracy hasn’t diminished - I’m not a very good reloader or a very good shot but throughout the barrel life I’ve seen no noticeable deterioration in accuracy, velocity, SD or ES whether I chased the lands or not. My velocities at almost 2,000 rounds are pretty much identical to those after the first 150 rounds (I did record a noticeable acceleration in velocity from 30 rounds through to 115) and my SD is never far from the 6-8 range from new to now (credit the barrel, the smith and good components). 

Thirdly, I do not pause between shots to allow the barrel to cool. I suspect that if you do, barrel wear would be more modest but it’s nothing I’ve tested. In fact, I’m the opposite end of the spectrum. I sometimes shoot 200+ rounds in a day and I don’t make any attempt to let the barrel cool & I live with the consequences. I will often shoot 10-20 rounds quite rapidly and as you can see, I’m loading to a respectable velocity. Again, load slower, shoot slower and i suspect barrel wear would be more modest.

So in my experience barrel wear is something I can live with. I’m not chasing the final 100 rounds of barrel life, accuracy is good enough for me (I’m not a benchrest shooter obviously) and N550 has been an excellent powder, easy to meter, easy to find and it produces the velocities I need. 

I only have a couple of gripes with N550. Firstly, temp sensitivity. Across a spread of over 50F change, I’ve recorded close to a 1FPS change per F degree change. It’s not quite linear but almost. I took some rounds to Florida last year and tested velocities on the same day at the same range from dawn at 40F through to mid pm at over 100F. The rounds were kept outside but in the shade and I tried to be disciplined in a bid to generate accurate data.

Whilst I’ve not had an opportunity to repeat this test in a single day in the U.K., chronographing over the winter here and hot summer did show similar results per 1F change.

Secondly, the 139gr Scenar needed just 40gr loads ie not very full cases. I could load more powder for more velocity but am now exploring alternative powders that will give slightly more case fill, maintain velocity at my target level but prove less temp sensitive and hopefully just as easy to load and source. 

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Thanks TJC. I also wanted opinions on the same. I load 6.5CM and use N150 which gives me around 2800 fps with around the 40 grain mark. That's in 139 scenar,  130 Sierra TMK, and the 143 ELD-X.  

Thanks for the info.

Apologies for "nicking" your post Badger..

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Thanks chaps for you positive replies. For other folk watching. Can any advise on the possible benefits of using a double based powder (eg Vit 540) over a single based (eg  Vit140) powder. Another example is R17 which has a reputation as a barrel burner would R16 for example be a better choice as an alternative?

I hope this will encourage a little more discussion.

Thanks

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1 hour ago, The Badger said:

Thanks chaps for you positive replies. For other folk watching. Can any advise on the possible benefits of using a double based powder (eg Vit 540) over a single based (eg  Vit140) powder. Another example is R17 which has a reputation as a barrel burner would R16 for example be a better choice as an alternative?

I hope this will encourage a little more discussion.

Thanks

Hi badger, I can't tell you much as I've only just started a tub of vn530, I use hbn on my bullets so allways end up over the max book loads . 

1.5 grns of vn133 over max is what I've been using with no problems

1.2 grns of vn530 over max gave me a blown primer, never had a blown primer before so would say n530 builds pressure a lot quicker than n133 .

I will use the tub of n530 as I got some nice groups with it and I always thought n133 was clean but the 530 is cleaner☺

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For what it's worth, according to the Reload Swiss catalogue, N550 has the same burn characteristics as Reloader 17, AKA RS 60.

I know from experience that stiff loads of RS 60 will toast the throat area of  a 6.5x47 Lothar s/steel barrel in 2000 rounds, and they're really hard.........

The barrel in question still shoots, though. I'm beginning to lean towards the idea mooted by some old time yank benchrest shooter (whose name I've long forgotten) when he said the only bits of the barrel that matter are the last six inches to the muzzle, and the crown.

In mine, the button chatter marks are still visible from 8 inches forward of the throat to the muzzle.

Pete

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18 hours ago, Bob57 said:

Hi badger, I can't tell you much as I've only just started a tub of vn530, I use hbn on my bullets so allways end up over the max book loads . 

1.5 grns of vn133 over max is what I've been using with no problems

1.2 grns of vn530 over max gave me a blown primer, never had a blown primer before so would say n530 builds pressure a lot quicker than n133 .

I will use the tub of n530 as I got some nice groups with it and I always thought n133 was clean but the 530 is cleaner☺

Hi Bob,

Can i ask what calibre and bullets were used for the data you posted?

Cheers

Chaz

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1 hour ago, chaz said:

Hi Bob,

Can i ask what calibre and bullets were used for the data you posted?

Cheers

Chaz

Hi Chaz,

.204 Ruger with 39 grn s/b/k . Have a look at my post on handloading headed ..204 Ruger with vn530

 

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4 hours ago, Re-Pete said:

For what it's worth, according to the Reload Swiss catalogue, N550 has the same burn characteristics as Reloader 17, AKA RS 60.

I know from experience that stiff loads of RS 60 will toast the throat area of  a 6.5x47 Lothar s/steel barrel in 2000 rounds, and they're really hard.........

The barrel in question still shoots, though. I'm beginning to lean towards the idea mooted by some old time yank benchrest shooter (whose name I've long forgotten) when he said the only bits of the barrel that matter are the last six inches to the muzzle, and the crown.

In mine, the button chatter marks are still visible from 8 inches forward of the throat to the muzzle.

Pete

If the bullet jacket doesn't make it that far, its slightly academic.....😂

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