Warning notice for Parker-Hale-style replacement nipples

[TFoley]

There are quite a few people here, me included, who shoot GENUINE Parker-Hale rifles of one kind or another. The later production of so-called Parker-Hale rifles with numbers higher than around 14000 or so, will, in all probability, be metric.

5/16" whit. 18 tpi. for Original Whitworth rifles and EARLY Parker Hale reproduction Enfields

5/16" whit. 20 tpi for Reproduction Whitworth rifles and LATER Parker Hale Enfields

I found out the hard way.

Sadly, there does not appear to be any definition of what, precisely, constitutes 'early' and 'later'. My Parker-Hale rifles, 420 and 1187, are both pretty early production, and, naturally, not being aware of the different versions, I got the wrong 'later' items.

 

[LawrenceA]

Thanks for the heads up

 

[Stantheman86]

Is there a safety issue where a later 5/16 nipple will fit an early Parker-Hale and blow out ?

 

[52Bore]

I’ve always believed the later PH made in Italy utilized metric M8x1.25 threads. (Nearly identical to 5/16-20).

 

[ResearchPress]

⁠A note was published in the MLAGBs 'Black Powder' magazine in 2003 warning that 'Parker-Hale' rifles marked 'Made in Italy' on the trigger guard have metric nipple threads. It noted "these threads are 8.0mm (0.315 ins) - very similar to the MLAGB nipples that have 5/16 ins (0.3125) Whitworth thread. THE THREAD PITCH IS NOT THE SAME. Do not try to force a nipple home, as the hardened thread on the nipple will damage the barrel." Reportedly this had caused a nipple to blow out; in that case a 5/16 in Whitworth thread forced into a metric thread in a 0.451 barrel.

David

 

[52Bore]

Threads per inch (tpi)
5/16-20 is obviously 20tpi
M8x1.25 equates to 20.3tpi
Being the length of a nipple thread is approximately 1/4” (0.25”) long:
20tpi x 0.25” = 5 threads
20.3 x 0.25” = 5.08 threads
With tolerances, they are interchangeable.