Take your can off!

Consider this to be a public service announcement.

Always, always, always remove your moderator from your rifle when it is not in use. This is an Accuracy International barrel that was returned to the cabinet with a reflex sound moderator still fitted.

It is a mess. That is not to say it is unsafe, however it is far from ideal. Interestingly the bore looked absolutely fine when I took a closer look with a bore ‘scope.

Also, please remember it is not only carbon steel barrels this applies to, stainless steel barrels can and do corrode as well.

While I am here, a quick update on the XM177E2 project, some more parts have arrived and hopefully I will be able to assemble and test fairly soon. Next job is to machine the correct receiver extension nut, the early versions were designed to be tightened with a pin spanner and the later are castellated. There are so many small details to get right if this to be vaguely true to original. Right now my number one mission is to find an aluminium butt stock which looks nigh on identical to the one in this picture but is not plastic.

 

The XM177E2 build continues

The customer had asked if they could come and watch key stages of the build and who am I to argue even if it is an unusual request. Luckily I know them very well.

Today was profile the barrel as per the previous exercise, carry out some basic assembly to confirm fit and modify the FSB (Front Sight base)

 

 

 

 

 

The original XM177E2 had the casting mark ground off on the rear of the base and the bayonet lug removed, so that is what I did. Note the tear drop forward assist on the main rifle picture, I am trying to get a look as close as possible to the original rifle.

The profiling went well although I did opt for a fine finish contrary to the original, I just could not live with the thought of building something that looked like it has been roughed out with a rasp on a Pole lathe…

I need the butt stock to arrive and we can then complete the assembly and run a couple of test rounds through it, then Cerakote and off to Proof. Oh, I also need to complete the muzzle device/sound moderator. I have decided to build it in three options:

1. Standard and 100% correct to the original Colt drawings.

2. Standard looking but for a spigoted barrel to give an 11.5″ overall look (XM177E2)

3. Standard looking but for a spigoted barrel to give an 10.0″ overall look (XM177)

I wonder how many people machined a barrel to the correct M177E2 profile today.

The picture shows the M177E2 11.5″ barrel look and the roll of hockey tape is there to hold the FSB up as it was just starting to rotate under its own weight which I think is a reasonable fit considering it will need painting.

Barrel profiling

There are probably a reasonable handful of people in this country who profile barrels in house and I do a modest number for ourselves and occasionally others RFD’s, however I always think it is rather special when I profile something out of the ordinary such as this one.

This is a dummy barrel to check the profile of a barrel destined for a Colt XM177E2 replica build, the only difference being the original barrel was 11.5″ in length and this one is 12″ to keep the build within the UK 12″/”4″ laws, or barrel length not less than 12″ and overall length not less than 24″

Why the test run? Well as much as I have confidence in my programming it is always nice to run the part in a soft metal first to confirm fit and this run exposed a tightness where the front sight base (FSB) fits which is annoying as I am good to the original drawing, albeit at the upper end so the FSB must be on the tight side and we have a stack up of tolerances. I will modify my program accordingly.

This was nice to machine as I did not need a steady due to the short length. Cycle time was a very steady 21 minutes and a few seconds and I will need to increase my feed speed on the finished article to leave some machining marks as the original would have had.

Chamber will be 5,56×45 NATO and it will be attached to an A1 upper and skinny hand guard.

Next job is machining the muzzle device which is a flash hider/sound moderator combination.

EDIT – In case you were wondering what an XM177E2 is I have attached an image from http://retroblackrifle.com/ who are my go to on-line reference for such things (Hope you don’t mind guys!)

Sound moderators

As well as designing and manufacturing our own sound moderators in house, we can supply and fit other makes when requested. Today was a Wildcat Predator 12 on a .308 Win Howa and as the Howa is pre threaded in 5/8″ UNEF it is just a matter of ordering it in and screwing it on, or nearly..

Firstly I like to correctly fit the rear bushing which means removing the bushing, screwing the moderator on, measuring the diameter of the barrel immediately behind the moderator and boring the bushing to suit.

People ask what the purpose of the bushing at the rear of a reflex moderator is and really, it serves a couple of purposes. Firstly it prevents excessive radial loads and damage to the moderator female thread where it is screwed on to the barrel and secondly, it allows the manufacturer to design a fairly generic back end to the moderator which can then be tidied up with the bushing.

I usually bore the moderator bushing with +0.25mm on the diameter of the barrel, or around 5 thou all round which is ample for expansion and general use. People ask why and there is an easy answer, it is my preference.

 

A Dremel is not the tool for opening the bushing and I seriously question why a person or shop would do this. It takes probably 25 minutes to measure, bore and fit the bushing, explain the safe use and maintenance of the sound moderator, fill in the table 1 of the new owners FAC and kick them out of the door and joking aside, I would always sooner spend 25 minutes explaining things and giving them a correctly fitted moderator, more to the point, we do not charge separately for this service.

I have read various views on bushing clearance and the implications of its lack of so I have added a picture of the moderator I run on my Accuracy International. It is a custom reflex with a stainless steel front and inner tube and an aluminium rear body, at the rear it is bushed with an internal O ring that contacts the barrel. Accuracy wise it works very well.

Once the bushing is bored and fitted I walk the customer through the do’s and don’ts of sound moderators. Never leave it on your rifle after you have been out shooting, regularly strip and clean the internals, keep an eye on any O’rings fitted and replace them if required and most importantly, lubricate the threads on the muzzle and the moderator with a wipe of copper grease or similar. WD40 will not do!

…and why am I telling you this? Because you need to know.

Triggers and trigger weights.

I am often asked to adjust and/or tune triggers and one thing often becomes apparent and that is people have no real concept of trigger weight.

Many years ago I was asked to service and adjust a sporting Sako trigger to 3.5lbs, which I did, the customer tried it when he came to collect the rifle and declared it was far too heavy. Well it was on exactly 3.5lbs and it turned out he wanted something closer to half that. Lesson learned for all of us.

In an ideal world I will make the adjustment whilst the customer is with me until we reach a weight that suits the customer.

The one thing that always worries me is when people make their own adjustments and fail to check the operation and safety of the rifle afterwards and I cannot over stress the importance of such checks. If in doubt, leave it alone or ask a grown up. Lighter is not always better!

I remember working on an F Class rifle a few years ago and commenting on just how horrendous the 2oz (55 grams) trigger was.The owner admitted later that it had failed in a competition and he shot the last few rounds by carefully closing the bolt to take the shot, so it was effectively slipping over the trigger sear as the handle was depressed. it reminds me of an F Class competition once when the competitor to my left was taking his first sighter, there was a shot followed by “Oops”

Anyway, this particular trigger job was an Anschütz 1807 and I was asked to increase the trigger weight and give it a once over.

First job always has to be to check the operation and confirm the existing trigger style and weight and this one was set to a scary 5-8 grams, I would hate to shoot it with cold fingers!

These days I use a Lyman trigger pull gauge, I misguidedly lent my old electronic gauge out and never got it back hence the Lyman. These are actually quite accurate and I sat down with a known weight and ran numerous tests when it first arrived and I would say it is accurate to +/- 1 gram which is quite an improvement on the more traditional spring gauges and tins of shot on a piece of string. Of course the accuracy is dependant on the way you use the gauge and yanking the trigger back with the gauge will give vastly overweight figures.

What I do like about the Anschütz triggers is the range of adjustments for sear engagement, first and second stages and trigger weight and these are one of my favourites. This particular trigger has now been cleaned and set to ~100 grams

What can you best do to keep your trigger in good working order? Well, avoiding contamination with bore cleaning solvents and oil is a good start. I always use a Cleaning rod guide/Bore guide (Obviously) and trap a piece of kitchen roll folded in half under the back of the guide to prevent the ingress of contaminants when cleaning.

If you need to clean a trigger in the field, remove the trigger, hold it in the same orientation as you would shoot the rifle and pour a liberal amount of lighter fluid in from the top, this will flush a lot of the contamination and gunk away and when the fluid dries it leaves a slight residue that aids in lubricating the trigger until you can get it checked and cleaned properly.

DO NOT dump the contents of a can of brake cleaner followed by a liberal coating of gun oil and certainly do not put WD40 near it as you will be back to square one.

Do not lighten your standard trigger excessively and always, always check the operation before use.

And why am I telling you this? Because you need to know.