OzFclass

Had an NRAA 155gr HBC round left over today so I pulled the bullet to see what powder and charge weight is used. Found this stuff on the bullets... any idea what it may be?

Brad Y
There was a time when the factory ammo had the projectiles shellacked or glued in to the cases to get them to develop the required velocity. It is possibly the way it is still done. Maybe a call to your state association or the manufacturer could shed some light on it.
Regards Malcolm.

Thanks Malcolm. If they need to generate pressure to get a certain velocity, is there any problem with bumping up another grain or so of powder??? There werent any visible pressure signs that I could see, though my rifle has a very long throat.

Brad Y
Not sure what powder is used in the factory rounds as sometimes manufacturers get a specially blended powder which can't be duplicated by what you and I can purchase. It is never a good idea to assume that you can use what the factory says is in them as the burning rates of the commercially available powder lots can be different. Work up loads with the powder you have irrespective of what may be in the factory loads.
Regards Malcolm.

Thanks mate. I make a point of doing it- especially new calibres Im not familiar with. Using 2208 now but with the 26" barrel im thinking 2206H might be a good powder.

What was the weight of the powder charge in your Winchester/HBC Palma round ???

43.9gr is what I weighed

43.9 grs?

Looks like Winchester are sitting on a truck load of 2206,

They surely wouldn't be using their 'own' propellants,

Wonder what they would do through a chrono.

John

Brad, the compound is a sealant, it used to be a tar based sealant and any fouling created by this tar was removed with “wombat’s piss” which was a mixture of eucalyptus oil, tee tree oil and oil of cloves and a darn good scrubbing. I am not sure whether a water based compound is used today.

This “tar” is flexible, and heaven forbid that some bright spark would attempt to glue a projectile in place which could fuse projectile and case depending on the compound in an attempt to get more pressure in a perceived edge on the competition from ideas gleaned from viewing the posts.

During testing for the NRAA some years ago, I visited the Winchester factory and discussed the issue of sealant and fouling and grouping. Winchester have an underground 100 yard range for testing. In responding to the issue of fouling Winchester tested cartridges without sealant and found their groups opened up and were not meeting their quality assurance standard. Groups with sealant generated consistent velocities. There is a big difference between higher pressures and consistent pressures. A flexible sealant produces velocities that are marginally higher.

It is interesting to note that the ammunition produced for the Australia Match at Bisley by the Geelong plant then, using the sealant, saw the English Team shoot a record score and my concern that the ammunition could take on moisture during air travel never eventuated.
Hope this helps, David.

Looking at it, I believe its 2206H, but cant confirm it. Powder charge would be about right. Its definitely not win powder. Didnt chrony it but surely it would be made to do the 2900+fps velocity from a full 30" barrel.

A tar like substance was what I thought it may be. Havent bore scoped the barrel since shooting, but the boretech eliminator and iosso paste would have removed it I reckon.

The powder is 2206H.
The load of 43.9 is consistant with the conservative policy of Winchester.
Doubtful as to whether that load will achieve 2900 in some barrels ( 30 " )
in mid winter.
As David said the tar based compound is a sealant, nothing else, and is a carry over from ADI days when it was used exclusively in ADI produced ammo purely as a Tropical sealant.

Barry

Could it be used to achieve uniform neck tension with inconsistent brass?

I understand that it's something like that, but more along the lines of achieving a specified neck tension.

Johnk, you are correct.

David