Mk IV Block Cracked

**Barnettshale** · 02-28-2011 09:57 AM

I went to the range yesterday and shot 4 rounds through my MkIV. Got home yesterday evening and removed the block to clean it. Cleaned and oiled it and while looking closely noticed a hairline crack on the left side, midway between the face and the rear of the block at the top. The wing area to the left of the dish where you slide round down into the chamber. I didn't notice this before so have no idea how long the crack has been there. When I get home tonight I will see if I can take pictures so others will know what to look for. It bothers me enough that I just ordered a replacement from IMA, along with another trigger spring. I made a replacement trigger spring for one of my Francottes but it was labor intensive and I had to do it twice because I didn't temper the first one correctly and it broke right off the bat. My trigger spring is definately the culprit in the heavy, 10#+ trigger pull I have.

Information

Warning: This is a relatively older thread
This discussion is older than 360 days. Some information contained in it may no longer be current.

**Highly Recommended** · 02-28-2011 09:57 AM

A Collector's View - The SMLE Short Magazine Lee Enfield 1903-1989. It is 300 8.5x11 inch pages with 1,000+ photo’s, most in color, and each book is serial-numbered. Covering the SMLE from 1903 to the end of production in India in 1989 it looks at how each model differs and manufacturer differences from a collecting point of view along with the major accessories that could be attached to the rifle. For the record this is not a moneymaker, I hope just to break even, eventually, at $80/book plus shipping. In the USA shipping is $5.00 for media mail. I will accept PayPal, Zelle, MO and good old checks (and cash if you want to stop by for a tour!). CLICK BANNER to send me a PM for International pricing and shipping.

Manufacturer of various vintage rifle scopes for the 1903 such as our M73G4 (reproduction of the Weaver 330C) and Malcolm 8X Gen II (Unertl reproduction). Several of our scopes are used in the CMP Vintage Sniper competition on top of 1903 rifles.

Brian Dick ... BDL Ltd. - Specializing in British and Commonwealth weapons

Specializing in premium ammunition and reloading components.

Your source for the finest in High Power Competition Gear.

Here at T-bones Shipwrighting we specialise in vintage service rifle: re-barrelling, bedding, repairs, modifications and accurizing. We also provide importation services for firearms, parts and weapons, for both private or commercial businesses.

**Barnettshale** · 03-01-2011 07:33 AM

**martini** · 03-04-2011 01:53 PM

I'm surprised if this was caused by firing, the block is in compression.

**Barnettshale** · 03-07-2011 11:28 AM

I don't know what caused the crack but it appeared to start between the stamps on the left side.

Actually the crack starts at the tip of the wing of the "W" and runs upward. I think it is the stamping of the WD caused a stress riser.
The "W" on one side and the "4" on the other side. Also the block does not have much meat there. I got my replacement block and it looks good.

I ended up swapping strikers and striker retaining nuts between the MkIV and MkII blocks. Also swapped tumblers between the MkIV and the MkII. Cleaned up the trigger assembly and loosened the trigger spring screw a bit. A really good trigger now.

**martini** · 03-08-2011 01:23 PM

It looks like a fatigue crack.

Have you tried cleaning it up on the side with emery paper? It will not solve the crack but you may see the crack is in fact longer.

In any case it looks like a goner.

Thread: Mk IV Block Cracked

Thread Tools

Search Thread

Display

Mk IV Block Cracked

Thank You to Barnettshale For This Useful Post:

Similar Threads

Cracked receiver on an M17

Cracked necks in 6.5 x 55 brass.

Cracked Tang!!

Swede M96 with cracked stock-HOW TO FIX?

How common is a cracked gas cylinder?

Tags for this Thread

Posting Permissions