Vihta N540 in 6BR

[eddyverhoeven]

In recent testing I found that N540 is very accurate in combination with the 105gr. Lapua Scenars,Moly). Accuracy is equal to the best load I have with Norma's 203B in my gun which has a Border cut rifling 1 in 8 barrel.

The load is as follows :

Case : Lapua
Primer : CCI BR4
Bullet : Lapua 105 grs Scenar Moly
COAL : 2.366' - jumped 0.005'
Load : 31.8grs N540

I would like to try this load in 300 meter prone competition but several of my fellow shooters claim this powder will ruin my barrel very quickly, some say even after a match or two.

300 meter prone competition is very demanding on barrels as one fires 65 to 75 shots in less than 75 minutes, sighters included. The barrel tends to get very hot,too hot to touch) during summer matches.

Normal useful barrel life in my gun,with N140 and Norma 203B)has been between 2200,Shilen) and 3400,Border) shots.

My question is could I use N540 for my matches or should I stay away from it?

I think German Salazar has used this powder in his high power competition but I am not sure.

Eddy

 

[spclark]

I'd be hard pressed to believe any appropriate powder for a given caliber or cartridge would ruin a barrel in a match or two. Did any of the detractors offer up what might be valid reasons for their opinions?

Generally the N-series rifle propellants from VV are very clean-burning so it can't be powder fouling they're concerned about.

Heat is the barrel killer true enough! Even at better than a round a minute your prone shooting won't exceed the heat of OTC rapid fire events where you shoot 10 shots a minute, twice in two relays twice a day for an 80-round match. I know shooters who use N540 for their match rifles & they're not burning barrels up in a match or two. If they shoot a lot - every other weekend for 6 months - they might shoot a barrel out in a season but that's still a lot of shooting.

Close to 32 grains of anything is a decent charge of propellant i 6BR; against the popular load of 30 grains Varget, your barrel may fade faster from the volume of powder being burned rather than the particular brand / type.

Interesting that you like 203-B. I bought five pounds last year, found it a bit slower than RL15 in 6HAGAR,about the same case capacity as 6BR) so plan to use it this year shooting JLK175 VLD's in .308. Tried N540 too in the 6HAGAR & went with the RL15 for the extra speed; Carl Bernosky used N540 I think in the last two NRA HP National wins at Camp Perry,'08 & '06 shooting his 6HAGAR AR spacegun.

Don, I'm curious how you ferreted out those specs for burn heat? You have numbers for other popular propellants,H4350, RL15, Varget to name three) you could share? Or a link where the data can be found?

 

[JRS]

Have you tried NORMA 202? I have had excellent results with it. I believe NORMA started loading their factory ammo with this now rather than the 203B they used to use in the 6BR case with both the 105 and 107.

 

[spclark]

JRS - No, the 203B I have now is the first Norma propellant I've ever used. Norma's not too commonly available... but then not much is right now, is it?

Gunamonth - You may be right but as I don't use,let alone own) a 'PC' I can't run it. I suppose I could buy a copy of Windows to run on my Intel Mac but to be honest I'd rather buy more bullets & propellants & primers,when I can find them :-< ).

They're all in the same range, eh? I wonder what propellants we might want to use would be vastly hotter - or cooler, for that matter?

 

[TonyR]

N540 has been the most accorate powder in my 6mm BR F-Class gun s well. I have a 31' Krieger 1:8 and I have been shooting the Berger 105 VLDs at around 2900 with anywhere from 29.8gr to 30.6gr with no signs of pressure. This gun was chambered for the 107 SMK so the 105 VLD seats out into the neck a little so be careful and work up with these loads in your gun. I stopped going going up with the powder when the vetical started to open up. I have been using the CCI 450 primers. I seat the Bergers .010-.015 into the lands. I heard the same story about barrel life and I could find no basis for it. I have put about 500 rounds through the gun with N560 and the throat has moved out maybe .010.

 

[12man]

How does the VV N540 do with the lighter bullets in the 80 - 95 grains range? I know it is popular with the 105 grain bullets. With todays powder access problems I would like to Diversify some of my loads and have some N540 to burn THANKS MUCH

 

[TonyR]

Lighter bullets and N540 worked fine in my gun. I shot the Berger 95 VLD all the way to 1000 yards with nice round holes. Never did serious load development. I don't remember the MV.

 

[JRS]

How does the VV N540 do with the lighter bullets in the 80 - 95 grains range? I know it is popular with the 105 grain bullets. With todays powder access problems I would like to Diversify some of my loads and have some N540 to burn THANKS MUCH

I can't speak for the N540, but I have gotten great accuracy with the BIB'S 95Gr bullet in a 1:9 twist barrel at 3070 fps using NORMA 202.

 

[12man]

THANKS I DO HAVE SOME 95 BIBS FOR MY 1-10 TWIST I'LL TRY THE 202

 

[JRS]

The best and lowest priced source for NORMA powders is Powder Valley. That is, if you don't have it.
Your 1:10 twist is precisely the twist Randy Robinett recommends for the 95. I struck a happy medium to be able to shoot his 95 and 108.

 

[GermanS1]

Eddy, I normally use RL15 which is almost identical to N203b in my 6BR. I have a good supply of N540 for it and was going to shoot it this season, but other projects got in the way. I previously shot a lot of N560 in a completely different caliber and there was no change in the rate of throat erosion from single-base powders like H4350 or H4831.

Many people in our hobby repeat what they hear so often that even as technology improves, these old legends last for generations. That is the case with double-base powders. When Hercules,now Alliant) first developed double-base powders in the early part of the 20th Century, they did wear barrels faster. However, it didn't take them long to develop coatings that brought the rate of erosion back in line with single-base powders.

VihtaVouri has developed that science even further and no one should have any concerns about barrel life simply because a powder is double-base. In fact, the RL15 which I use,and 203b) are double-base powders so I don't think you will see any difference at all in barrel life. If N540 shoots better in your rifle, then use it without concern.

 

[eddyverhoeven]

Thanks guys,

I got the answers I needed and will use the N540. If I notice any difference in barrel longevity, I'll report it to you.

This site really is a great help to all shooters

Eddy

 

[kevinbritvec]

I really like N-540 in .223 with 69/77 bullets. European shooters have been reporting reduced barrel life when compared to Vihtavuori's standard fare. I haven't been able to wear my barrel out yet, despite my best efforts. I don't discount their observations, but believe German's take on this issue is probably closer to the truth. Once stated, often repeated.

 

[yat3b35]

The best and lowest priced source for NORMA powders is Powder Valley. That is, if you don't have it.
Your 1:10 twist is precisely the twist Randy Robinett recommends for the 95. I struck a happy medium to be able to shoot his 95 and 108.

I just ordered what Randy had left of his 95 gr fb 6mm bullets in stock. He told me he no longer going to make the 108 fb 6mm bullet. He has in fact started making a 6mm 108 BT bullet, but it is not up for sale yet as he is having it tested.He said they are looking promising though. The man testing them has been trying to get them to come apart at high rpms and thus far none have. If he gets them working as good as his Bib 30 cal 118 gr bullets Berger better look out and Randy better hire some help. Randy makes some of the best bullets I've ever put down range. John

 

[RDavies]

Its an old post, but one I have a question about. How have you found the N540 powder as far as temperature stability? As in, if you develope a load for it in winter, will the velocity go up a lot in summer, making it harder to keep in tune?

 

[afy]

While I am no competition shooter, nor an expert in my limited experience with N 540 across multiple calibers I have not found any differences in performance due to temperature.
No bolt stickyness, or flattened/cratered primers for loads that were done in winter and shot in summer or vice versa.

 

[TonyR]

We discussed this issue some time back in this thread:

http://6mmbr.websitetoolbox.com/post?id=3438087

 

[jpx2rk]

12 yr old thread ?????