Batch to batch Vihta Vuori powder deviations?

[blkbrd]

Has anyone noticed a difference on the cronograph of in burn rates from batch to batch of VV320 or other VV powders?

I have seen small deviations in burn rate from differant batches of rifle powders like RL15, but am wondering about pistol powders specifically Vihta Vuori?

See my changeover results 9 posts down.

[TriggerT]

Can't say about 320, but I have never had any problems with 310.

[Rob Bagnato]

I haven't had any problems with either N320 or N105.

[A33435]

I don't see it as a problem because each time a open a new 2kg can of N340 (thats at least 3 times in a year) i will check my loads for pf with a chronograph.

Recently i noticed with the newest lot (made from 2003) of VV i need more powder to get the same PF. The worth is that VV gave there powder more volume. Double charges can be detected easier by eye that way.

Therefore they added more non burning material. You will notice that too.

To give you an indication, with the older lots of VV N340 i used 5.2 grain under a 190 grain FMJ PRVI .40 for an average PF of 175. Now i use 5.5 grain N340

Greetings

Adrie

[L9X25]

Blkbrd,

My N-105 is usually only available in 1 lb bottles so I usually buy my powder in cases and that gives me several containers that are all from the same "lot" or "batch" and there is no difference between containers with the same lot or batch numbers. However, I have noticed differences when I start a new case with different lot numbers. Sometimes the difference is minimal and sometimes the difference is noticeable.

Leo

[OpnBlstr]

I have noticed up to a .4gr difference between lots of VV320 in 40S&W to maintain power factor.

VV310 has been quite uniform between lots as has N160 in rifle cartridges.

Now that I am loading 3n38 in 38 Super I have noticed wide swings there as well.

My load using 9.2grs of 3n38 shoots 176pf. A friend of mine using this same load chronos 155pf from the same pistol. That is a large variation in my book. I also noticed that dropping this load from 9.2 to 9.1 reduced my pf from 176 to 166!

I usually either buy 4 pounders of the VV or several single pound containers at the same time from the same lot. Then I work up a load and set aside some of that powder lot for big matches where I need to be sure of pf.

None of this really bothers me much since I value the extremely clean burning properties more than a few extra trips to the range for chronoing.

[.40AET]

Hey wait a minute. VV is the MOST expensive powder on the market. I was hoping to hear better results than what's been reported so far. I don't mind paying for clean burning consistant powder, but it is appearently only clean. Thanks guys, I'll be sure to chrono the next 8lb lot.

[kevin c]

My experience with Viht 320 is different from OpnBlstr's. My major PF .40 load is only 0.1 grain different on the three batches of powder I've used (8# each), loading the same components to the same OAL and shot through the same gun, of course.

Expensive? Yes. Accurate? Yes. Consistent? For me, yes. Clean and smoke free? Yes and yes. Relatively soft? Yes. Better than Clays or Titegroup? Don't ask me, 'cause I don't care - I've got a load I like.

And, yes, like OpnBlstr, I chrono every batch of new powder, and make any (small) adjustment necessary. And since, for me, it is becoming a pain in the patootie to rework my load for each new batch of whatever component, I, like many, buy and stock enough of every component so that frequent fine tuning is not needed.

[n2299]

This is interesting....

I just switched over to N320 from Titegroup recently so I haven't loaded enough of it to notice any difference.

I wonder if some VV powders are more sensitive to enivormental changes either during transit or storage, and thus explaining some of these differneces????

[gm iprod]

Hodgdon has some of the best batch to batch consistancy around, V V is only just 2nd, everybody else is worse.

Always, always buy the biggest amount you can afford from the same batch. I buy in minimums of 10lb before I open the last can of what I am using. I then Check that batch against the one I am using.

Hodgdon TG and V V 320 are probably the two most consistant powders I have ever used, Varget for rifles being another goodie. I buy V V 320 in 15KG (33lb) cases, this should last about 10years. I last bought TG in a 20lb lot, all the same batch about two years ago. I need more soon.

When I travelled to the US in May last year I got, I think, 4lb from Hodgdon and checked my loads. With the exact same brand of cases, projectiles and primers, I was less than 10fps different (out of 1200fps).

Check everything twice.

Better than Clays or Titegroup? Don't ask me, 'cause I don't care - I've got a load I like.

Thats the best system.

[blkbrd]

Ok after lots of chrono work, Here are the results from my VV320 lot changeover.

My old 8lb. lot of VV320 #642/02, 02334, 13.11.2002 would throw at 4.85gr. from my Dillon 650.

This 40S&W 180 gr Zero JHP load @ 1.20" @ 65F, would go 939FPS, PF 169.0, SD5, @65F.

Just changing lots over to lot # 657/02, 00009, 5.29.2003, changed the weight per charge to 4.8gr, a drop of .05gr.

This changed the velocity to 920FPS, PF 165.7, SD4, @65F. Just for info this is with the dial at 10:30 on my 650 powder measure.

As this is a bit close to the PF limit, I added .10 gr. up to 4.90gr. which is 12:00 on my powder measure, and got 940FPS, PF 169.2, SD 6 @ 65F.

FYI; I have found that my VV320 loads will go up from 169PF @ 65F, to 171PF @ 80F.

Results;

Lot changeover dropped the charge weight from 4.85gr to 4.80gr, had to go to 4.90gr to make it back to same power factor.

[ErikW]

You have got one fast barrel. A 6" maybe?

[kevin c]

I'm not sure that a .05 grain difference in thrown charge weight is that reproducible. At least in my Dillon measure, comparing carefully thrown ten charge batches shows a +/- variation of .2 or .3 grains, which would be .02 or .03 per charge. The charge to charge variation might be actually larger than that, but wouldn't be detectable on a scale that is only accurate to the nearest tenth.

I get good SD's from my 320 loads, but the same batch of ammo through my gun, shot under the same conditions, varies more than what you get. Still, it makes major, stays at major (mostly, see below), and the load and the gun are way more accurate than I am, so that's good enough for me.

I also, have found 320 to be temp sensitive. The biggest variation is not from environmental temp, but barrel temp. I consistently find that the first round shot from a cold barrel is significantly slower (10 to 20 fps, equalling 1.8 to 3.6 PF points) than subsequent rounds from the now heated up bbl. This impacts making major at matches, so I like to give myself a cushion, PF wise.

[blkbrd]

Its a Nowlin 5" with a long throat and tight chamber, it is to bad my ammo won't make major in any gun but mine, super accurate too.

My 650 throws charges +/- .01gr., avg. for 10, almost like clockwork. I let the case feeder feed cases and short stroke one time so I get a powder charge and not punch the primer, makes for a consistant charging on lots of 10 ea. cases.

It will throw the first few shots a bit slower like almost any gun.

[BSeevers]

I have shot 3n37 for something like 10 years(since it came out) Its so consistant I load to a 177/167 PF and have made it at 100's of majors. I check it very often as I carry a chrono and have this confidence because of that.

Now when my barrel and brass were wearing out I saw PF drop. When something changes something is broke, usually , I don't crank the powder measure or grind on the guide rod, extractor, etc. I find it. That old barrel was almost a smooth bore. Still accurate but had grooves and bumpy grooves. New barrel and back to 167 PF. I do not touch my powder measure. I do reload very deliberately though with my brand and brass only. Now 320 needs a little bigger load say 168/169 because the case isn't filled and for me has wider variences. I have have a chrono guy tilt guns back before firing to "help" shooters