.577 Enfield accuracy.

[enfield2band]

I had an interesting conversation with a friend of mine about .577" Enfields, original and reproduction.

He and a few others keep a record of their scores, which is generally in the high 80's and 90's at 100 yards. From reading the previous scores over 12 months, and for previous years, they noticed that they only achieved high scores in spring and autumn. In summer the scores were poor.
They concluded that it must be down to the ambient temperature. They reckon that because the rifling on the .577" Enfield is only about .003" the bullets are not setting up in the rifling because the barrel has expanded enough to stop the bullet setting up in the rifling.
Increasing the powder charge so the bullet expands into the rifling makes no difference.

Has anyone else came across this type of thing happening?

[ResearchPress]

They reckon that because the rifling on the .577" Enfield is only about .003" the bullets are not setting up in the rifling because the barrel has expanded enough to stop the bullet setting up in the rifling.

Excepting the earliest Patterns, Enfield rifles had progressive depth rifling, the P.53 for example being 0.015 deep at the breech and 0.005 at the muzzle. Parker-Hale used progressive depth rifling on their reproductions. So, on firing, the bullet expands to fill the deeper rifling, and is then swaged a little as it travels down the bore.

One variable creeping in as the summer months come and temperatures warm is the lube they are using. It may perform better in cooler temperatures? It could also be something external - do they always shoot on the same range; perhaps height of the sun and light and shade on the sights or target is detrimental to accurate shooting in the summer? Maybe the shooters themselves shoot better in the spring and autumn - are they wearing the same thickness clothing year round?

Lots of variables to consider... just a few passing thoughts.

David

[Hares Ear]

Blooming Heck
David Minshall, how are you keeping sir? I rarely visit this site much nowadays, but it's good to catch up occasionally and even better to see someone with such knowledge of the black art. Now if Neil Aspinshaw were to drop by as well?

Oh, back on topic.
My money is on the lubricant. I realised a long while ago that I needed two different brews. One Summer, and one Winter.

[ResearchPress]

Blooming Heck....

New playground for me.... didn't realise BP & Muzzleloaders fell under this forum until recently! I have Neil's new M-H book sat next to me...

David

[tacfoley]

New playground for me.... didn't realise BP & Muzzleloaders fell under this forum until recently! I have Neil's new M-H book sat next to me...

David

Some of us are also on muzzleloadingforum.com...