Viht N555

Malxwal

Well-Known Member
Looking for feedback from anybody using N555 in any of the common 6.5 chamberings, 55, Creed, 47.
 
Used it behind some 130 gr Sierras to run a new barrel in, and have chrono’d 41.5 gr of it behind some 143 eld-x at 2680 through a 26” barrel. I’ve loaded another .5 grains in the next batch, and Viht data tells me there’s still another full grain to go. Grouping nicely so far, some serious development on the way, so will check back if the threads still going.

It’s a bit bulky. It’s already getting near the top of some star line LRP cases, nothing a bit of tapping and settling won’t fix. and it somehow doesn’t flow very freely
 
Vihtavuori developed this grade with the 6.5 Creedmoor and similar applications very much in mind, so it ought to perform at least reasonably. By 'high-energy' (infused nitroglycerin) powder standards it is very mild, the lowest specific energy rating of the N500 series by far and in terms of 'combined heat of explosion' energy levels the same as some N100 series grades.

Burning rate wise, its designation might make people think it's close to the longstanding N550 - it's not, being a very much slower burning grade. Look at Viht's loads data for the 12 cartridges with N555 data so far and for bullet combinations with N550, 555, and 160 powders and you see a large gap between 550 and 555 in maximum charge weights, but a close correlation between maximum charges for N555 and N160, at least until you get to the two largest cased cartridges listed (30-06 and 284 Win) where N555 drops down a grain weight or two.

I've tried it in 260 Rem and 7mm-08 and it looks like it'll be a good alternative to the now lost 4350s. The former cartridge's results can be seen here:

FROM THE HAND-LOADING BENCH BY LAURIE HOLLAND

and the 7-08 findings will be published within the next few weeks.

(Incidentally, if looking for an IMR/Hodgdon 4350 replacement in cartridges like the 6.5 Creedmoor or similar mid-sized cartridges, the single-based Reload Swiss RS62 is an excellent choice and difficult to improve upon with the exception of those looking for absolute top MVs.)
 
Vit555 & n160 variations hope it’s of some use
 

Attachments

  • 9837C906-2C5A-4CE1-9EAD-7D45E6631A8A.webp
    9837C906-2C5A-4CE1-9EAD-7D45E6631A8A.webp
    262.8 KB · Views: 71
  • D5260797-8532-4BA6-8A12-E8BEA8EC2C1A.webp
    D5260797-8532-4BA6-8A12-E8BEA8EC2C1A.webp
    106.2 KB · Views: 47
  • DF7A772A-C648-4FF2-B738-FBA3A7E9F294.webp
    DF7A772A-C648-4FF2-B738-FBA3A7E9F294.webp
    122 KB · Views: 69
  • BD1835DC-1B0C-4180-A8A5-BAC5AB9E10CB.webp
    BD1835DC-1B0C-4180-A8A5-BAC5AB9E10CB.webp
    221.6 KB · Views: 80
Sorry in advance for hijacking this thread but I think there is some overlap...

I've just got hold of some N555 for my 6.5 Creedmoor and will be working up a new load with Sierra 130gn TGK.

The starting load on the Vith website is 37.8g however I'm using Large Rifle Primers instead of SRP as listed below. Can anyone tell me whether it makes any difference at all / is it safe to start with the same load using LRP?

And secondly, does anyone have a tried and tested load? I appreciate every rifle is different etc. but I'm wondering if I should start at 40gn which is well within the max.

Thanks all!

Screenshot 2026-07-10 at 15.07.48.webp
 
Thanks for the comparison @Edinburgh Rifles - very interesting, although having just bought a tub of N555 I'm going to work with it for the time being.

If anyone can answer my original question about rifle primers I'd very very grateful!
 
Thanks for the comparison @Edinburgh Rifles - very interesting, although having just bought a tub of N555 I'm going to work with it for the time being.

If anyone can answer my original question about rifle primers I'd very very grateful!
Start at minimum charge weight as per Vihtavouri, you'll be safe at that.
 
I am Using it for several 6.5CM loads. Sako S20
Lapua SRP, 45gn 127LRX. 2850fps. 10 shot ground under 3/4".

Lapua SRP 43.2gn. 130TGK. 2745fps. 10 shot 1/2"

Sako LRP brass. 42.4gn 130TGK. 2725fps. Same accuracy.

Sako Brass, 41gn. 140gn Gameking, 2600fps. Didn't bother shooting paper as I was just getting rid of 60 I found in a box. But 10 shots into a 3" gong at 300 yards. Just found what appeared a speed node and seated to 2.297" BTO. Then the rest went into a deer sized deer at a variety of ranges.

The 130gn TGK loas in Sako brass has worked in my rifle, and two other mate's rifles. Speed was different, accuracy wasnt.
 
I am Using it for several 6.5CM loads. Sako S20
Lapua SRP, 45gn 127LRX. 2850fps. 10 shot ground under 3/4".

Lapua SRP 43.2gn. 130TGK. 2745fps. 10 shot 1/2"

Sako LRP brass. 42.4gn 130TGK. 2725fps. Same accuracy.

Sako Brass, 41gn. 140gn Gameking, 2600fps. Didn't bother shooting paper as I was just getting rid of 60 I found in a box. But 10 shots into a 3" gong at 300 yards. Just found what appeared a speed node and seated to 2.297" BTO. Then the rest went into a deer sized deer at a variety of ranges.

The 130gn TGK loas in Sako brass has worked in my rifle, and two other mate's rifles. Speed was different, accuracy wasnt.
Very helpful, thank you!
 
Back
Top