Non select single triggers

A new reamer arrived from BBT (http://www.bbt.scot/) yesterday.

I have some new ejectors to fit in an over and under 12 Bore shotgun and ejectors often come without the cartridge rim cut-out so time for a new reamer and who else to speak to than Border Ballistic Technology as they are UK based and they always supply a quality product in a timely manner. On this occasion I contacted Dr Geoffrey Kolbe of BBT and explained what I needed and he said he would have a think about the design and get it sorted and this is what it looks like. I do like the BBT take on the design and look forward to using it later this week.

BBT say the following:

The problems with rim cutters for chambers like the 12 bore is firstly to ensure the cutter stays centred and concentric to the chamber, secondly that the cutter is well supported and thirdly that it does not chatter. Offerings by other reamer manufacturers do not seem to satisfy these requirements well, so we have developed this rim cutter, seen above.

12 bore rim cutter detail The rim cutter is supported by the pilot which locates in the bore at the front. There is a sliding tapered cylinder which sits in the back of the chamber, so the cutter well supported and yet able to slide freely on the cutting axis. The tolerance and concentricity of the pilot and sliding tapered cylinder ensure the cutter is very well centred to the chamber.

We see a lot of sporting guns at this time of year and as the season progresses things come in showing signs of wear and tear, mainsprings fail, firing pins burn, safeties fall apart and things generally start to rattle loose.

With a fortnight left in the season a non select single trigger shotgun arrived. It was failing to fire the second barrel so time for a complete strip and inspect and here is a rather poor image of the trigger assembly partly stripped down on the bench. This particular shotgun is probably around 100 years old and caused some head scratching before I identified the issue and I can say with some conviction that I am now intimately acquainted with such triggers. The gun was serviced at the same time and I took it out for a test firing yesterday and everything looks good so the gun can be collected by its owner for another days shooting.

Today I really hope I can get back on machining, with only two of us in the workshop it is so easy for one side of the business to slip and right now I have both gun work and machining to get on with if we are too keep customers smiling.

Snow outside and 6C in the workshop suggests Winter has not left the Wolds quite yet which is probably why I am so looking forward to my next cup of coffee 🙂

 

 

Two and a half years later…

We moved to the Lincolnshire Wolds just over two and a half years ago after 15 years in a Bedfordshire village which of course means 15 years worth of stuff to pack and move. For the most it all went well and we now have a significantly larger workshop in a far nicer part of the country, however I have always wondered what happened to my RCBS hand priming tools.

I knew they had been packed so they must have come here however they failed to surface which infuriated me as I had spent some time tuning them to give a better feel, removed the sharp edges and generally made them mine so there was no way I was just going to head out and buy some more especially given the replacement cost, even if you can buy this style here in the UK these days.

So I decided to go for an interim replacement until they were found. First option was the Lyman E-ZEE Prime which in my eyes is a simply dreadful device and it was soon relegated to a shelf and replaced with a Forster Bench Coax Priming Tool which allows me to change cartridges and primer sizes fairly quickly. The Forster is certainly a good tool however it is quite fiddly to load primers to and I was still yearning for my RCBS primer tools however by this time I was beginning to suspect they had been binned along with some wrapping or packing boxes or similar even though the Viking and I are very careful about such things.

This morning I headed down to the workshop to prepare for Monday as I have four rush gun smithing jobs to get out (More on these at a later date as they are all interesting and fairly unusual)

It was at this point that I heard an exclamation from the Viking, she was unpacking/unwrapping some items from the cottage living room (Yes 2.5 years later) and guess what she had found.

Now I have to ask myself how they managed to end up in a box of ornaments from the living room and I can only assume I came in with them from the Shed and asked her to pack them somewhere safe. I still have all of the primer trays neatly labelled and stored in a drawer in the armoury as I was always convinced the tools would turn up, eventually. So, anyone need a Forster bench primer system? 🙂

Yesterday I was out with the Labrador on a Beaters’ day which means we get to shoot and the guns beat for us and it was an absolutely brilliant day. The Labrador looks happy even though I did not give him a great deal to pick up. No matter as I now have two brace of Pheasants hanging up and I am looking forward to eating them at a later date.

This season is nearly over now, the Labrador only has a few more working days and then he is finished until the coming season however we do have some Pigeons to deal with if the rape in this image is anything to go on, so some more picking up for him and some more food for the freezer which is always good as I do like Pigeon.

I have never been happy with the rings fitted to my Model 1930 FN Mauser so I ordered a set of High Turret rings over the Christmas break and they arrived yesterday.  I deliberately chose the screwed two piece type rings as opposed to the original solder ring type as it is important to me that this rifle is not misrepresented in any way. The ‘scope is a rather battered/well used 6×45 Pecar Champion that was given to me a while ago, I do like the Champion as the 4 way Heavy Duplex style reticle is always centred in the image and you have the advantage of superb glass and an interchangeable reticle system.  I hope this will be a good combination of ‘scope and rifle for shorter distances.

I do have a Kar98K stock that the barrelled action could be dropped into and I always liked the Kar98K stock aesthetically, it has the turned down bolt cut-out and I find it to be very comfortable to shoot however I am slightly uncomfortable about making such a change plus it is nigh on identical to the model 1930 fit wise.  It will be an ‘On the day’ decision as the rifle has got to come apart to allow me to fit the receiver in my fixture to ensure the ‘scope brackets are correctly aligned.  Right now the new rings are the biggest investment in this project and even then the whole thing including the superb Model 22 trigger complete with prototype hanger very kindly donated by Robert Chombart has still come to significantly less than GBP200.00 according to my reckoning.

Odd how I seem to get so much pleasure from Pre-45 Action rifles these days as opposed to the more sanitised modern offerings with the guaranteed of sub MOA performance without effort. Col. Townsend Whelen is quoted as saying ‘Only accurate rifles are interesting’ and I could certainly not disagree however these older rifle offer a fascinating insight into a sometimes forgotten era of shooting that we owe a great deal to.

Video – Screwcutting COAL gauge tubes

I seldom post videos unless I think it is something interesting however I was machining the centre tubes for our COAL gauges today and decided to video the screw cutting cycle as the thread is fine at 8X0,75mm and the machine was running at 1000 Revolutions/minute.

OK so that was the plan, run a cycle and video it, however running coolant would mean the guards had to be closed and filming through a screen would mostly reveal coolant splashing in all directions so I opted to give the part a squirt of oil and run it and that was a bit of a problem in that you can clearly hear it sounding slightly rough towards the end of the cycle, the good news is the part was OK and the cutter still seems happy.

Anyway, the technical bit:

Machine: Harrison 400T  teach CNC centre lathe

Spindle speed: 1000 RPM

No of passes: 15 + 2 spring passes

Thread: 8×0,75mm Class 3A

Material: 316 Seamless thick wall stainless tube

Cycle time: Around 42 seconds

Operator: Me of course although the Viking did wander over to see what I was doing which is handy as she should really be running this sort of job.

Yes I know the tool is sticking out a fair bit however it is normally used for a different threading job with the tail stock in place hence the need to hang it out a bit more than normal.

303 Case Head Separation – A bit more

Following on from my previous post regarding fire forming .303 brass (First shot) with an O’Ring seated tight to the cartridge rim, this image shows from top to bottom:

No1 New and unfired .303 brass.

No2 Once fired with O’Ring .303 brass.

No3 Once fired without O’Ring .303 brass.

No4 Shows what can eventually happen as the case is repeatedly stretched and full length re-sized between shots.

No2 has been shot once and the overall length is now +.009″/0,02mm to factory length which gives an indication of how far the shoulder and neck has moved forward.

No3 is from a P14 with a reasonable chamber however after just one shot you can see indication of stretching as a shiny section just in front of the rim. The actual case length is now +.007.5″/0,02mm so shorter than that fired in the Lee Speed.

The difference in shoulder profiles is interesting, No2 being a commercial BSA Lee Speed probably built around 1900 and No3 being a Remington built P14 from around 1917 so it is worth remembering not all rifle chambers are equal and especially not the .303 service rifles from the first quarter of the last century

No4 is from a 1915 BSA No1 Mk3* that was well past its sell by date and sadly had to be retired for a number of reasons.

The 303 and ‘O’Rings.

If you shoot and reload for a .303 chambered rifle you probably know all about case head separation. This is where the case stretches and thins just in front of the rim and eventually fails leaving a cartridge case minus the rim stuck in the chamber. The good news is the remains of the case is usually easily removed, either with a phosphor bronze brush or a broken case extractor. I have used both methods in the past however if you can avoid the issue in the first place life is a lot easier.

Today was a bit of change of plan and saw us at the range complete with the Lurcher at midday, the Labrador being otherwise indisposed leaping around picking up Pheasants and Partridges.  The Lurcher is always happy to get out to the range as it means he can meet and greet people, run around like a, well like a Lurcher and once tired he spends some quality time sleeping in the back of the Landrover whilst we shoot, talk and generally enjoy ourselves. It works well for all parties concerned.

As this was a bit of a last minute thing we opted to take four rifles. The Schmidt Rubin M1911 chambered in 7,5×55 Swiss. A BSA Lee Speed (Sporter) chambered in .303 British along with a BSA No1 Mk3 Sporter, again in .303 British and finally the Savage M1899 chambered in 22 Savage High Power. The middle two rifles being .303 were in dire need of some new brass and this gave me the opportunity to show you how I fire form my .303 Brass.

The vast majority of people load their favourite .303 round typically with around 41,0 grains of N140 behind a 174 grain SMK which works well for distance stuff and is a reasonable approximation of MkVII Ball. Get it right and you have a superbly accurate round. Incidentally, I usually start at around 39,0 grains of N140 and work up, I have also found similar loads with RS50 (What was TR140) work equally well although RS50 appears to fractionally slower than N140 which is not a bad thing. Whatever you opt for please do ensure it is safe for you rifle.

Once loaded it is simply a matter of stuffing the round in your rifle and pulling the trigger in a safe manner. Well nearly…

The thing about military rifles chambered in .303 is the chambers can be rather generous, after all they were designed to be used in war where a shot was fired and the spent cartridge case discarded. The military certainly were not interested in preserving fired cases and a generous chamber meant the round could be chambered in muddy or dusty conditions which it did admirably. The downside is the cartridge case which head spaces off the rim tended to rattle around inside the chamber when ignited, the shoulders would go forward however the rim would go back and this would lead to stretching/thinning of the brass just forward of the rim, this can be evident on even once fired cases where the stretched area of material is clearly evident.

This leads to case failure in time so if I have a new box of brass to work with I add an O’ring to the rear of the case just in front of the rim. This means when the bolt is closed the O’ring compresses and holds the case head tight to the bolt face and as the internal ballistics take place the case head stays where it is and the shoulder moves forward. Yes the case has stretched but in a far more manageable manner.

You can clearly see the difference in the shoulder position on this ‘Before and After’ image.I guess a picture of a case shot without an O’ring would be good at this stage however it would also seriously upset my nice neat rows of fired brass as there would be a gap.

I will look out for a stretched case and add it to this post if I find one.

Look carefully and you will spot a ring on the bullet just behind the meplat, this is where the seater stem has been cutting into the jacket as it is designed for a 174 SMK as opposed to a 150 grain soft nosed bullet such as the Pro Hunter here. I will machine a new seater stem to suit the profile of the 150 at some stage however as today was a combination of zeroing and blowing the cases neck forward it was not incredibly important.

So there you are, fire formed 303 brass that should last for ages with neck sizing only and an occasional annealing. Before you ask, the O’rings I use are actually those used on our .308 Cleaning Rod Guides and I leave the ordering of such things to the Viking and have long since forgotten the details, however if you would really like to know give her a shout and I am sure she will be able to help 🙂