Never tell me it cannot be done, the M54S LSR rifle

[Ovenpaa]

The Viking and I have started shooting LSR (Lightweight Sport Rifle) The rules we shoot to are very simple, .22 LR or Air rifle, no bondage jackets, trigger weight is free, any sights other than laser and a maximum all up weight not exceeding 4.5kgs (10lbs ish) and that is about it. People seem to favour the CZ452 or the 10/22 and as we do not have a 10/22 here we tried a CZ that was set-up for Rabbiting without too much luck. Next time out it was the same rifle, different 'scope and still not great. So I looked in the armoury and spotted a 54 Match; so off came the standard sights and a 9x 'scope went on. A quick check of the scales confirmed it was way too heavy even though it shot reasonably well off-hand (We both shoot 4.75kg springers in Bell target) So we decided to build our own chassis and get the rifle down to sub 4.5kgs, mostly because I was told it could never be done.

The design had to be tube based as I have worked on them several times in the past, a simple design that is readily adjustable for most people/disciplines, uses off the shelf material sizes where possible and sensibly priced. keeping the barrel low in the hand always helps as well.

With the design finalised the weight was calculated and I soon realised I would struggle to get to target with the original 580,0mm tube design, so two shorter versions were added. This weekend we worked on the 430mm tube length which in theory gets it to 4450 grams with 'scope and rings so I just scrape in.

The tube was the main part of the weekend's work, it is a 40,0mm x 5,0mm wall thickness and the 54 receiver although 30,0mm OD did not quite fit so I ended up having to bore out 0,25mm x 210,0 long.This proved to be a swine of a job and next time I will use a reamer. The OD was reduced to 38,0mm with a taper to 36,0mm however I did not hit my target weight so back into the machine it went and some grooves were added. These actually give a reasonable hand grip although I may add a couple more towards the receiver as the stop short right now. More importantly, it saved an additional 38,0 grams which is where I need to be and I will use the grooves as stop points for the slots that need to be added.

The trigger guard was a scrap one from the CG days and the hand grip will be binned in favour of a lighter AR15 type.

The cheek piece will be made from Kydex on the light version and aluminium on other versions.

The name M54S-430 is simply because the barrelled action is a Anschütz Match 54 S stands for SHED and the 430 is the length of the tube.

This is the weekend's work:

[bradaz11]

this is looking awesome Dave, as I've said on FB, this looks the mutts, it's also just the thing that could get me shooting my 1813 again

[Alpha1]

I like it. I will watch with interest how this develops.

[Pippin89]

Brilliant work! Well done... Something in the back of my head is saying that if you use a glove that is included in the total weight too? Is that correct or am I going mad again?

[Ovenpaa]

Pippin, you are correct, the glove if used is included in the weight, a bit like F/TR and the bipod. It is something I need to keep in mind, however getting it under weight is my first goal.

Today's image, the cheek piece is one of the original CG ones that sat too high, so it is on here only as a reference unless I can do something with it.

[Ovenpaa]

I needed to machine the adapter that goes between the main tube and the rear tube. It serves multiple purposes, it joins the main tube and barrelled action to the butt stock and cheek piece, it acts as the rear mounting point for the hand guard hanger and it also acts as the recoil lug.

To explain; the receiver is held in place within the tube by two M6x0,75mm screws, the rear one also acting as the front fixing for the hand guard hanger on this chassis. Now we all know the .22LR is not the heaviest of recoiling rifles, however with time it is going to rattle the fixings within the aluminium tube. I could always add steel bushings, or bond the receiver in place (Removing it would be a tad awkward) I could machine a slot and cross plate to replicate the recoil lug, but that adds some complexity (Read time and cost) So the easiest way is to use the adapter as the recoil lug, so the rear of the receiver butts up tight against it. The rear adapter is screwed to the tube and the job done!

Of course I also need to keep the weight down, so I have added a broad groove to the angle section of the adapter to replicate the front section and added a cut to the front end of the external surface of the rear tube. It serves no purpose as the lower tube hanger will never go that far forward, well not unless I want to reduce the length of pull to 200,0mm/8.0" (Doubtful!)

So there you go, another design stage sketched out. I was on the big machine for 3-4 hours first thing in the morning so I added it as the last job.

I am scratching around for spare minutes to get this done and despite not having a great deal to show, I am hoping to shoot it a week Wednesday, so just into March. My goal is simply to put some test shots down range so it may not be to weight at that stage, regardless I am looking forward to making a noise with it.

The adapter is machined and the chassis is now officially below my target weight however I will continue to shave ozs/grams whenever the opportunity arises. I doubt I will find time to do much more this week, however come the weekend the plan is to slot the tube to accept the receiver and fit a sight rail so it can be checked for fit and balance. Right now I am stuck for a couple of M6x 0.75mm (M6 Fine) cap head screws around 10-15mm long, so if you have a couple in a draw or know anyone in the UK who does high tensile fine screws without a minimum order of 100 units please shout!

[Les]

What is the total length with the butt stock removed?

[Ovenpaa]

The tube is 430,0mm. The complete front end (Tube with receiver and barrel) is 856,0mm so it always stays within the 12"/24" law. The minimum barrel length you can have to stay legal with the front end only is 390,0mm/15.5" ish

[bradaz11]

for a max weight saving project, there are a lot more holes to be drilled and grams to be shaved in that chunk yet

[Ovenpaa]

Bradaz11, yes there is loads to be lost yet. I have all the cut-outs for the receiver including the bolt, load port and a cut out for the safety flag. Then there are all of the lightening cuts on the tube itself and I can certainly shorten the 25,0mm and 19,0mm tubes or possibly even go to thick wall carbon fibre for these two parts.