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PH-5A is in error by 17% for its range settings?

Printed From: Enfield-Rifles.com
Category: Enfields
Forum Name: Enfield Accessories
Forum Description: Slings, Bandoleers and any other Accessories for the Enfields
URL: http://www.enfield-rifles.com/forum_posts.asp?TID=8567
Printed Date: July 22 2018 at 7:19pm
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Topic: PH-5A is in error by 17% for its range settings?
Posted By: Shamu
Subject: PH-5A is in error by 17% for its range settings?
Date Posted: September 28 2017 at 1:44pm
News to me but I just read that any PH-5 fitted to an SMLE is 1/6ths off for distance. Supposedly the reason is they were calibrated for a Long Lee so there's a velocity difference & a sight radius difference that combined mean you need to use  6 clicks to get the effect of 5 on the range scale.
Any observations or thoughts?
Confused
Its an early 5A with the 1/2 MOA clicks BTW.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)



Replies:
Posted By: evanguy
Date Posted: September 28 2017 at 3:05pm
Ohh ok so it is one of the 1/2 moa units not the PH minutes sight, so that ideas out.

I have the exact same sight as you, now i want to check if its the same with mine.


Posted By: Canuck
Date Posted: September 28 2017 at 3:11pm
I read the exact same article a couple days ago.

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Castles made of sand slip into the sea.....eventually


Posted By: Shamu
Date Posted: September 29 2017 at 6:16am
Suddenly, out of the blue there's this Revelation that no-one ever heard of before!
Hmmmm?


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Zed
Date Posted: September 29 2017 at 11:12am
It would also be for original ammo so probably irrelevant for your reloads anyway!

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It's nice to be important, but it's more important to be nice!


Posted By: Shamu
Date Posted: September 29 2017 at 2:21pm
Yes, I usually run 150 Gr at about 2550 FPS, so its more a curiosity than anything.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: britrifles
Date Posted: March 27 2018 at 9:24am
This OP six months old, but got me thinking.
I'll dig up my copy of the PH Service Rifle score book, it discusses the PH 5 sights fitted to the No. 1 and No. 4 rifles.
The PH 5c sight with the 1/4 MOA knobs fitted does not give 1/4 MOA clicks on a No. 4 rifle, it's off by about 1/5 if I remember right (4 clicks = approx. 1.25 inches at 100 Yds).  I'm going by memory here, but I'll confirm.  It becomes evident if you use the MOA elevation settings for the various ranges published in the PH scorebook for the PH 5 sight, these settings are lower in MOA than actual.  I figured this out when I plugged the data for my loads into Strelok ballistic program and compared them to the MOA range table in the PH SR Scorebook. 
 
The range scale on the PH 5c sight seemed pretty close, even with my hand loads (174 gr SMK at MV of 2400 fps) going from 200 to 300 to 600 yds.  One of these days I'll try it with MK VIIz ammunition.
 
Is the sight radius different on a No. 1 vs No. 4 rifle with a PH 5 sight installed?  I think the Elevation vs Range tables were different for these rifles with the PH 5 sight.
 
I also checked the Mk I machined Singer rear sight on the No. 4; 1 MOA clicks; approx. 0.0075 in/click. 
 
 
 
 
 
 
 



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