Barrel fluting

We also flute barrels occasionally…

Fluting is one of those jobs that you just have to get on with. I would love to say we are currently fluting on a three axis CNC mill however we are not. Instead, we use a Bridgeport manual and either a dividing head or a rotary table, we have a variety of different ‘Turny-roundy-indexy’ sort of things in the workshop, however it is often down to what is on the machine.

On this occasion I used what was on the machine as it was already set up. This particular rotary table can be moved in two axis and currently wears a 4 jaw chuck with a collet block in it, so it was just a matter of set it to zero degrees and pop a collet in it.Incidentally, the writing on the table are notes from a previous job.

At the other end is a tail stock and with the barrel in place, the penultimate  job is to check everything is correctly setup across all axis and fit the support.

The support (Not shown) either supports the centre of the barrel from the back or bottom and is either an angle plate or a jacking plate dependant on if I am fluting from above with a carbide bull nosed cutter or to the side with a rotary cutter.

The customer had asked for 8x6mm flutes so bull  nose it was.

At this point it is a matter of setting the start point, feed speed and depth of cut and kicking the job off. The downside is it a messy job on a manual and very time consuming and this stainless barrel was fluted over an evening and the following morning.

I have fluted many barrels and handled many more and my pet hate is sharp edges on the flutes so I always take care to de-burr them, ideally they are then blasted and Cerakoted however this barrel was stainless and the customer preferred a self colour finish.

So there you are a heavy stainless  barrel fluted.

The technical bit:

8×6.0mm equispaced flutes cut to 3,0mm deep.

Length of cuts 330,0mm

Total weight saving 295 grams

Screw cutting and Sound Moderators

Credit where credit is due. Wildcat moderators, lovely products, fully strippable, every single part available as a spare and always a super cheery service, even on a Monday and most importantly, made in Great Britain. Thank you Alison at Wildcat.

This one was destined for a beautiful Steyr Luxus and although I did the machining a while ago it is only now that I actually got around to taking the pictures (Complete with fluff) Plus blacking the thread. The crown is a 90 degree which I do for all barrels I thread for sound moderators unless otherwise instructed, the reason being the crown is easier to clean and an undercut or 11 degree crown is unnecessary as the moderators keeps the crown protected.

Feel free to argue 🙂

I just noticed the cutters in the picture. We are experimenting with different makes of cutter at the moment for both the manual and CNC lathes and these were one of the contenders, I am now on a box of German manufactured inserts which are  looking good so far.

We have an active policy of buying British first, then European, then further afield if necessary and I strongly believe it is false economy to buy unbranded inserts.

On the subject of machining, this thread was cut on the 1970’s Colchester Chipmaster we have here. The ‘Chippie’ is a manual lathe although we did upgrade it to DRO (Digital Read Out) a few years ago. This lathe is always a delight to use and cuts superb threads every single time.

.303 Throat Gauges

We all know someone with a .303 rifle, or own one ourselves.

In fact I believe all new FAC holders should get out and shoot one at some point, just because. I have a modest collection of 303 Sporting and military rifles, including Lee Speed and postwar No1Mk3 commercial examples here in the armoury along with later ones such as the 1920 Lithgow below.

One thing I can usually say about the .303 rifle is it will have been shot, usually shot a lot and accuracy does suffer after a while. Now accuracy is not always a good reason to buy a rifle and I have rifles here that will not shoot a hand span group at a 100 yet they are keepers, equally I have worked with rifles capable of shooting tiny groups at extremely long distances that have left me cold.

For me, the majority of .303s are usually very special rifles and to find one that shoots is even better, so how to determine if the rifle in your hands is going to shoot? Well range time is the simple answer, however you can also check a few areas before taking the rifle out and bore and throat erosion are always good places to start. A careful peer up a barrel tells you a lot however a shiny bore is not always a good bore and if the throat has disappeared 3/4″ up the barrel you are always going to chase accuracy. So I made some throat gauges for just this reason and here is a prototype and an early version.

Use is very simple, just remove the bolt and drop the gauge into the chamber. The amount of the relieved section visible gives an instant indication of throat erosion. This is not an absolute measurement and just because the throat has gone does not mean the rifle should be put back in the rack, however if you gauge two identical looking rifles and one swallows the gauge you know which one to test shoot first.

So there you go, one small area to check when considering a .303 purchase. I should probably sit down and write a book of such tips however not all of them are going to interest people.

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

A new machine has arrived

A new/old machine arrived last week, a little Herbert Junior manual surface grinder that will be perfect for recoil lugs, flat sided firing pins, anything that needs a ground finish, oh and maybe the occasional blade or two. I have been on the lookout for something like this for ages so to find one within 15 miles and at a really sensible price is a real stroke of luck.

Was I excited? Nah! More like skipping around!!!!!

The little surface grinder was unloaded via a pallet truck from a trailer. Putting it on at the other end was easy enough as there was a fork lift truck. Here we were not so lucky and we ended up moving the grinder off the truck and onto the workshop floor. From there it was picked on a sack barrow which was precarious and eventually it was rolled into its new location.

This is exactly as it arrived other than I have re-fitted the spark guard on the left hand side of the bed. Looking it over in the cold light of day it was in remarkably good condition, virtually zero backlash on both axis which have vernier scales in metric and imperial which is good as I prefer metric yet people often send me drawings with imperial dimensions.

I will probably fit a single axis Digital Read Out (DRO) at some stage on the Z Axis as I run DRO’s on all of our workshop machines and have been spoilt by them over the years. There is no real need to fit a DRO to the and Y axis.

It is a heavy little thing at around 230kg and that is mostly cast iron to soak up resonance and vibration, so despite being manual travel I expect reasonable/good finishes.

The thing just to the left is a Thermal Arc AC/DC Tig welder. I will not be using either the grinder or welder on a daily basis so they can share the same space and although there is room to use both from the same area I will probably drag the welder out when either machine is in use.

Yes, the missing paint on the base is hacking me off so I will do something about it.

With the three phase supply run in the little Surface Grinder was powered up. It went the wrong way of course and that was only after I had reset the starter which had tripped, probably due to the rattly journey home.

First job was dress the wheel, a little diamond dresser came with the machine, just clamp it down with the magnetic chuck and off you go, well not quite… The thing about surface grinders is they/you have the ability to hurl items across the workshop with a total disregard for life and limb. so always set the dresser to the ‘safe’ side of the wheel, that is the side that the wheel has gone past the the 180 degree mark and is starting to rise (Clockwise rotation would be to the left) So if you are dim enough to take too heavy a cut the part will fly into the spark tray without having to go through the wheel which invariably turns into a DiY hand grenade at that point.

A slight kiss was all that was needed to bring the wheel true and square.

Next job was check the magnetic chuck to the wheel. Runout/Parallelism across the length of the chuck ( X Axis) was 0,013mm or 0.0005″ across 200mm/8.0″ of travel.

Back to front (Y Axis) slightly less. So OK ish however I will take a closer look at some point.

Time to get grinding. With the wheel dressed I found a suitable piece of steel in the oddments bin and got to it.

First impressions are wow, the machine is very smooth running, as expected and this really poor picture cannot portray just how pleased I am for a first attempt.

A worthy addition to the workshop and roll on the first proper job with it

I still need to properly level and bolt it down and fit a new wheel to it at some point however it is already giving superb results and its first job is due in very shortly so I had better get some floor fixings and the engineers levels out.

 

Ruger Precision Rifle rear bag riders.

I forgot to post a picture of our latest Ruger Precision Rifle rear bag rider plates fresh back from anodising so here is one.

Machined from 6082 aluminium and satin anodised finish they are virtually a direct copy of the original butt plate however they are extended to accept a bag rider tube. You have a choice of either a self colour 1,5mm tube (Shown in picture) This adds around 65,0 grams to the all up weight of your rifle. Alternatively you can have the 20,0mm carbon fibre tube version with polished aluminium ends which is a lot lighter. (Guess who forgot to weigh the last ones he built)

Everyone tells me these make a huge difference to the tracking of the RPR at both short and long distances and coupled with the 6.5CM cartridge gets you into some very long distance shooting.

I also have a single bracket in a lovely shiny aluminium finish if anyone is interested.

I also forgot to add a link to the Ruger Precision Rifle rear bag rider on our site, so here it is:

https://www.shootingshed.co.uk/oscom/product_info.php…

I am hearing good things from the people who have already received them, it makes me wish I had an RPR myself!