I guess my powder is past it?

[fizzbangwhallop]

Having picked up my .20Prac Sako A1 from Neil Mckillop a couple of summers ago I've been reloading using an old tub of Viht N133....... I'm sure I've read that powder goes off but you can tell that by the smell losing that ammonia type edge...... the tub still has that whiff.

 

There's nothing untoward in the performance and I get good grouping at 24grns at an average of 3671fps which is pretty much on a par, or even slightly less of a charge, with what other .20Prac owners load to.

 

But I do get staining/acid etching of the next bullet head loaded into the chamber after firing a shot......... the smell of the fired shot is sulphurous.

 

The round on the right was chambered for 2 hours after 10 shots zeroing 2 'scopes to the rifle. (On a side note I'm really impressed with the new Photon XT 6.5!) The barrel was cool between shots walking to and from the target each time.

 

Shot 4 foxes with the rifle last night within a half hour slot and the middle bullet is the one chambered after that for another 3/4 of an hour.

 

The fired cases all extracted as you'd expect without signs of undue pressure...... I'd have thought the presence of fluid around the bullet must be increasing the pressure too!

 

Is my powder past it's best?

 

 

 

 

 

 

Cheers

 

Fizz

Gonna post this on one or two other forums as not a bad thing for loaders to be aware of look out for.

[GeorgeB]

Looks like you left bore solvent in the barrel which has then reacted with the bullet jacket.

[fizzbangwhallop]

Looks like you left bore solvent in the barrel which has then reacted with the bullet jacket.

Hmmmm... interesting...... I can see where you're coming from. I use Forrest Foam and always patch until dry.

 

I'd have thought that would have been cleared by previous shots. I don't get it on a cartridge extracted unfired however long that may have been in the chamber.

 

I don't get the same effect in my .17Rem using a pot of N135 that's more recent.

 

Cheers

 

Fizz

[Laurie]

That's not powder related. If you have powder deterioration problems, the kernels become either 'sweaty' and start clumping together, or alternatively the opposite where it has dried out and starts producing dust. As soon as it breaks down, the smell changes to a sour vinegary aroma.

 

The powder manufacturers say powder should last 10 years if properly stored, which in our climate basically means keeping the can lid tightly closed and adopting fairly common-sense practices on where it's kept, how long it's exposed to air etc. How often the powder is used in small quantities (ie exposed to air in a powder measure etc and then returned to the can) could affect life slightly. In practice, it usually lasts much longer than 10 years especially ball powders and basic single-based extruded stick types. 'High-energy' types such as the Viht N500 series and Alliant powders can see some of the nitroglycerine migrate out and this doesn't ruin the powder rather makes it faster burning which can create a slight risk for those using it in maximum loads.

 

I briefly used Forrest foam and found it hard to remove completely through patching out. I got similar effects to those you're seeing but on the case walls allied to a slight lubrication effect that increased pressures. Also, as it was a match rifle, cartridges were only chambered for very short periods unlike your use, but even so half a dozen cases ended up discoloured to a greater or lesser extent until I realised I had a problem and got the chamber mop / lug cleaning tool out. I've never used this cleaner since.

[fizzbangwhallop]

Thanks Laurie,

 

The powder isn't showing any of the breaking down symptoms you describe..... loaded a batch in early April and again in mid-May and the kernels were flowing through a Targetmaster without problem with no dust remaining in the hopper afterwards.

 

Both replies so far on the SD suggest it's probably post-shot condensation collecting around the bullet which I don't disagree with.... exacerbated by having the muzzle up post-shot whether that be resting the rifle on the high seat rail, on a bipod or in the back of a truck foxing. Not helped by the moderator either.

 

I was just half wondering if old powder had the capacity for a higher moisture content... or the residue in the barrel.

 

As to way's of avoiding it.... as suggested elsewhere it's not always practical to leave the bolt open, or wait until a your quarry comes into view before chambering a round and I don't think it would dry out that quickly anyway with such a small bore..... or to point the barrel down letting it drain towards the mod.

 

atb

 

Fizz

[gunner]

Hello sir fizz , that bore foam , have you used that from day 1 in that barrel ? - . I used it in my original hmr but ditched it soon as i didn't like the way its sticky on everything . Have you got any bore shine or wipe out or #9 or similar ? Thats what i would try. But , also have you got 2012 -2013 for example ? on the tub of n133 ? Mine has the year of manufacturing in the front sticker !

By comparison , my prac is 23.3 of n133 giving 3652 , almost the same velocity , 25 / ½ “ barrel . The other thing that springs to mind is bore guide ? Has the rubber O-ring worn ? Try a bit of bore foam on a naked woman / sorry Bullet ( not loaded of coarse ! ) for 1-2 hours and keep a beedy eye on it ? See if you get same reaction with copper ! Cheers timo.

[andybrock]

I had exactly that same problem with my PPC when I tried using foam, the only way I could get all the foam out was to literally swill the chamber and barrel out with brake cleaning fluid, only used the foam a couple of times absolute pain in the ar5e stuff.