Progressive depth rifling questions

[kh54]

I have collected for shooting a number of ACW period reproduction muskets, mostly Enfields and Springfields. I have Parker Hale Birmingham Enfields, Miroku Springfields, and Italian representations of a handful of other muzzleloading musket types. I understand that no Italian manufacturer has provided progressive depth rifling for any modern reproductions but that Parker Hale’s reproductions are so rifled. What about Miroku military reproductions? Anyone know? And how can one even tell whether or not the rifling is progressive depth? I would appreciate any insight.

 

[Some_Mook]

I have collected for shooting a number of ACW period reproduction muskets, mostly Enfields and Springfields. I have Parker Hale Birmingham Enfields, Miroku Springfields, and Italian representations of a handful of other muzzleloading musket types. I understand that no Italian manufacturer has provided progressive depth rifling for any modern reproductions but that Parker Hale’s reproductions are so rifled. What about Miroku military reproductions? Anyone know? And how can one even tell whether or not the rifling is progressive depth? I would appreciate any insight.

Remove the breach plug, Pin gauge the depth of rifling at the breach and then compare to the measurements you get at the muzzle.

If you are shooting correct reproductions of military loadings, and get good accuracy at the distances you shoot, it really doesn't matter, does it?

 

[TFoley]

Remove the breach plug, Pin gauge the depth of rifling at the breach and then compare to the measurements you get at the muzzle.

If you are shooting correct reproductions of military loadings, and get good accuracy at the distances you shoot, it really doesn't matter, does it?

Remove the breech plug of a Parker-Hale rifle? Good luck with that.

 

[Some_Mook]

Remove the breech plug of a Parker-Hale rifle? Good luck with that.

Parker Hale are produced with progressive depth rifling. OP seemed to know that. I took the OP's question to be regarding Miroku, since that was the specific question.

 

[kh54]

If you are shooting correct reproductions of military loadings, and get good accuracy at the distances you shoot, it really doesn't matter, does it?

Enquiring minds want to know.

 

[Cubreac]

My understanding is that only those P-H rifles with serial numbers under 1500 have the progressive rifling.
@kh54 I envy your collection

 

[kh54]

Remove the breach plug, Pin gauge the depth of rifling at the breach and then compare to the measurements you get at the muzzle.

With respect, I don't believe that's correct. My understanding is that the land-to-land distance is constant and only the depth of the grooves changes, from something like .015 at the breech to .005 at the bore. So a pin gauge wouldn't establish that - right? (I've not used pin gauges so I'm genuinely asking if my understanding is correct.)

@Cubreac: I understood that about Parker Hales, and that's one of the reasons I worked for a few years to get good examples of the 1853, 1858 and 1861 patterns. They all shoot very well. My 1861 and 1863 Miroku Springfields are also very accurate and that's one of the reasons I asked about the rifling of the Mirokus. Regarding my collection - thanks for the compliment. My wife died a few years ago and I sort of went crazy collecting MZ firearms, I suppose as a way of coping. I would trade them all for just five minutes again with her.

 

[Nobade]

I have a 1863 Miroku and it does not have progressive depth rifling. I've never heard of any reproduction other than P-H that does.

 

[Dusty_Traveler]

A pin gauge will not work to measure rifling depth, but can be used to measure the bore diameter. Very accurately I might add.

 

[Some_Mook]

If one measures the diameter at 180° between a land and groove (or groove to groove if they line up at 180° from each other) on one end of a barrel and compares that measurement to what is obtained on the other end of the barrel, if the breach diameter measured was found to be greater than what was measured at the muzzle end, would that not be an indicator that the rifling was deeper at the breach end than at the muzzle end?

Is that not what the OP asked?

I was not trying to convey a method of measuring the depth of the rifling itself, just a simple method to determine if there was a difference from one end of the barrel to the other.

 

[dave951]

If one measures the diameter at 180° between a land and groove (or groove to groove if they line up at 180° from each other) on one end of a barrel and compares that measurement to what is obtained on the other end of the barrel, if the breach diameter measured was found to be greater than what was measured at the muzzle end, would that not be an indicator that the rifling was deeper at the breach end than at the muzzle end?

Is that not what the OP asked?

I was not trying to convey a method of measuring the depth of the rifling itself, just a simple method to determine if there was a difference from one end of the barrel to the other.

Unbreeching these rifles is not recommended unless there is an over riding mechanical reason to do so.

 

[kh54]

I was not trying to convey a method of measuring the depth of the rifling itself, just a simple method to determine if there was a difference from one end of the barrel to the other.

Ah-ha. I think I understand now. However, I'm not skilled or confident enough to remove the breech on any rifle. Otherwise it seems like an easy way to measure, though. Thanks!

 

[ResearchPress]

My understanding is that only those P-H rifles with serial numbers under 1500 have the progressive rifling.

Most P-H rifles with a serial number under 1500 were Volunteers or Whitworths. The Enfields don’t generally come in until, 1000+ and then not exclusively. All their Enfields as far as I know had progressive depth rifling.

David