Ruger MKIV & The LPA MKII adjustable sight compatibility

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Whatnickname

Bearcat
Joined
Dec 17, 2017
Messages
9
I acquired a MKIV hunter in blue recently. I went with the blued pistol because it's about half the price of a stainless steel gun and there are a ton of blued uppers on the market that can be had for a song. I purchased two Bull Barrel 5.5" uppers and a 4.75" Standard upper and have less than $200 in the three of them combined.

I prefer adjustable sights on my pistols. LPA makes an excellent adjustable sight that uses the standard front sight on the Standard 4.75" pistol. Called Ruger and was advised that the rear dovetail sight slot on the MKIV was the same dimension as the MKII & MKIII. So problem solved...not entirely. The LPA sight fit the dovetail perfectly. However, the pistol shot 4" high at 25 yards with the LPA sight cranked all the way down.

Called Ruger again and asked if I could purchase a higher front sight. Ruger: " No. All of our front sights are the same height." Me: " Is the front sight on the MKII higher than the MKIV?" Ruger: " Don't know. I would have to speak with one of the engineers." I could see where this was going so I thanked the customer service lady for her time and hung up.

Had a brief moment of inspiration and realized that I had a spare 4.75" barrel in my parts bin. Removed the front sights on both barrels and the MKII front sight is 25 thousands of an inch higher. The MKII sight is held in place with a roll pin. The MKIV sight is held in place with a 3/32" Allen screw. However, the holes line up perfectly. All that was needed was to drill the MKII pin hole out with a 3/32 bit and install the sight.

As of today, Numrich does not have any MKII front sights. Wirthwein Guns does have them. $10.00 + shipping. These sights do not have any pin hole and will have to be drilled.

Hope this is helpful.
 

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Rocdoc

Buckeye
Joined
Aug 23, 2008
Messages
1,440
Location
N. Texas
One thing I like about the MKIV is the clearnce page at Volquartsen, many different MKIV uppers come along there, inexpensive. I check that page often. Volquartsen also has a eBay page, got some good deals there on parts.
 

CHEVYINLINE6

Single-Sixer
Joined
Nov 29, 2022
Messages
399
Location
Vancouver Washington
As far as screw held down front sights like on bull barrel pistols, I bought several that were originally made for AMT Lightnings that had 3 different hieghts and fit my 5-1/2 inch Ruger bull barrel perfectly.
 

TestEngineer

Bearcat
Joined
Jan 7, 2022
Messages
91
Seems you still have a problem.

Rear sight blade to front blade on the short Standard barrel measures 7 5/16". By my calculations, raising the front sight by 0.025" is only going to lower your POI by 3.077". So you will still be high by 0.923" with your rear sight bottomed out.
 

BuckRimfire

Bearcat
Joined
Nov 7, 2012
Messages
66
As of today, Numrich does not have any MKII front sights. Wirthwein Guns does have them. $10.00 + shipping. These sights do not have any pin hole and will have to be drilled.

How close to the bottom of the blade is the hole in the original blade? Could you drill the hole in a new blank closer to the bottom of the blade to make it taller? It would teeter around on the pin, but you could fix that by applying drops of epoxy to the bottom at each and and sanding them down after they hardened. Make them just *slightly* too thick to give the roll pin some extra friction as it goes in.
 

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