777 Load Testing..

[Across The Pond]

Hi - for those that are interested, I did some further testing of 777 compression at the range today. This time with a larger .36 cal charge of 18gn/vol equivalent. Initially I tried a very light compression, no more than ensuring that the powder stack was up against the lubed under-ball wad. With a round ball seated just on the wad I experienced the 'double crack' ignition that I have seen before with lightly/uncompressed loads of 777.

There was no way to comment on loss of accuracy other than that the odd ignition made me push the gun and I put several shots low.

Next I tried a more significant compression, but still not 'crushing' the powder.
This bought back the proper ignition 'signature' and I managed a (typical for me) group of about 3" at thirty feet.

So... my 1st conclusion is that triple seven is very, very fussy stuff with regard compression.
2nd, the slightly larger load of 18gn/vol made 'feeling' the degree of compression easier for me, unlike the 15gn/vol charge. I guess this is because the rammer is moving less.

If anyone has an explanation for that odd 'double bang' ignition, I'd like to understand it...

I am reluctantly going to try Pyrodex P again next weekend (most likely the Monday!) so more results then.

Seasons greetingst to you all!

ATP

 

[Father Knows Best]

So... my 1st conclusion is that triple seven is very, very fussy stuff with regard compression.
2nd, the slightly larger load of 18gn/vol made 'feeling' the degree of compression easier for me, unlike the 15gn/vol charge. I guess this is because the rammer is moving less.

If anyone has an explanation for that odd 'double bang' ignition, I'd like to understand it...

That is indeed odd. Why don't you ask Hodgdon? I've been loading 777 in cartridges (44-40, mostly) for cowboy shooting for several years now, and never experienced any unusual ignition. I use mostly Winchester large pistol primers, though I have also used CCI 350 magnum large pistol. As you probably know, Hodgdon does NOT recommend any compression of 777 in cartridges. My most common load takes up about 3/4 of the case volume, and I use a fiber wad to eliminate any air space under the bullet. I have loaded some without the wad, however, when experimenting with loads. I never observed any unusual ignitions (they all sounded and felt fine), but I did see a jump in extreme spread and SD with the air space, so I went back to using the wad.

 

[Harve Curry]

Maybe Across the Pond's odd ignition is with the #11 percussion caps, not nearly as hot as center fire primers.

 

[Across The Pond]

Maybe Across the Pond's odd ignition is with the #11 percussion caps, not nearly as hot as center fire primers.

Interesting idea. I used CCI no.11 - I also have RWS no.1075 and Remington no.11 so will add these into the recipe next time I'm testing.

The odd firing signature is very like I imagine a superfast flintlock would sound - almost two separate discernable bangs - I wonder if the first one is the cap........

I love my cap'n'ball revos, but loading .38spl with a lubed bullet head, primer and 2.5Gns of bullseye was way, way easier than this!!!

ATP.