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CG INCH BENEFITS
There are many differences between the INCH, Barnard, and other typical single shot actions and the INCH. To begin with, The INCH is 38mm diameter and the Barnard 37mm diameter. The Barnard is 13mm longer than the INCH, with the latter being 187mm.
I would classify the important aspects as follows:
Starting with material, the Barnard like many actions, are made from low alloy steel as is typical for rifle actions, such as Remington etc. The body being made from commonly available EN24 (AISI 4340)
The bolt a higher spec EN362 (AISI 8620), which is a nitriding steel, not core hardening. Distortion means grinding after heat treatment, with tensions generated remaining within the material (and brittleness).
The CG INCH on the other hand is made from cold working tool steel, which has much higher properties in all aspects - hardness (wear resistance), toughness, shock resistance, resistance to galling etc - it is Böhler Uddeholm K600 material. Böhler is a European leader in special steels from Austria. (Note, real non-German orthograph of the name is Boehler)
---And in german it is Böhler !!! (So what?? Non Allemands won't care less)
This is very important on many levels: starting with heat treatment, the Böhler does not distort when being hardened (as it is designed for this aspect, and why we use it), whereas 4340 moves considerably, meaning there are post hardening treatments like grinding required. 4340 has a hardened state around 43HRC, which is less than K600 at 52HRC. This means two things: the 4340 is too soft as is, so requires surface hardening like Carbo-nitriding, the INCH of course does not require this due to the material being hard all the way through, not just the surface. The surface needs to be hard to provide long term use of the action (if you have seen a well used Musgrave, you will know what I mean).
We also offer surface treatments like Titanium Nitride, Titanium Aluminium Nitride and Chromium Nitride for a small extra fee. This applies to materials, as the process is done by the same people that do the heat treatment - being for the Body, bolt or both.
Titanium Nitride is a yellow gold colour, commonly seen on drill bits.
Titanium Aluminium Nitride is a more advanced treatment, and is a dark grey colour - common on expensive milling cutters.
Chromium Nitride is used more for reduction of friction, and is a nice light grey/silver colour.
There are other specialist coatings developed by individual companies for special work. Some of these come in red/brown colour, purple etc. They can be quite expensive.
The CG INCH is about 99% backwards compatible with the Millenium action/stock system. Which makes it easy for people to upgrade to the INCH from the Millenium if they so desire. The other thing is we have available the fleXibloc (and incidentally for the Barnard as well). This system was developed by HHE in NZ, and further developed by Robert Chombart (CG - as in CG Millenium, RPA CG 2000 etc).
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On the bedding block, we believe this is the best system of attaching the action to a stock, but we ultimately leave this decision to the customer and his chosen rifle builder. We do not use any other system on rifles we build for ourselves, or for standard factory rifles. We also believe that the "glass bedding" (epoxy bedding) is far inferior to this system (particularly when it rains!!). For the small added cost, we believe it is worth every cent. These blocks can be fitted either in a new stock, or any current one that a person likes, to convert over to the CG INCH system.
The function itself of the action is most excellent. One cannot begin to notice the big differences between the CG INCH rear locking system, and that of any typical front locker. The bolt throw is short - around 80mm, which is between 20-30mm less than any typical front locker. This has implications with cheek piece modification, but most of all, it allows the cheek piece to be modified much less. I shoot with the action very close to my face, so this is a real benefit for me.
The bolt handle lift and closing pressures are much the same as a Barnard, with the INCH bolt handle being very slightly shorter.
The firing pin travel on the INCH is only 4mm, generally at least 20% shorter than any other using a coil spring. The expected lock time is around 1.4 milliseconds. The CG INCH design uses a hammer and pin tip, not a one piece firing pin. This means the largest moving part in the firing system, actually works on the firing pin tip, as a hammer, which is how the light weight and high speeds can be attained. The INCH uses the well proven and reliable Belleville washer system. These are high quality USA alloy steel units, not the sometimes used inferior carbon steel units accessed in mainland Asia.
The firing pin tip is reversible. It is a double ended unit, so if on the rare occasion it may break, another spare tip is available on the other end of the tip to use. This can be done on the firing point with only a 5mm Allen wrench.
The lugs on the INCH are external to the bolt shank, not inside of it. This means a much larger area (both radial and circumferential) for the lugs, meaning a stronger action. It has been estimated up to 50 metric tonnes of force to press the bolt out the rear of the body.
The rear locking lugs have a hidden but very real advantage over front lugs: that of the way the force of the bolt face / case head operates on them. The closer the lugs are to the case head, the more the force is angled tangentially to the bore axis. This detracts from the ultimate strength of the action - the INCH has the lugs 100mm to the rear of the bolt face, giving very straight force lines, and therefore gaining the most advantage of the material strength. The INCH bolt is very heavy for this reason.
The standard CG INCH comes standard with the CG UNI trigger unit made by Tom Myers, from Cincinnati OHIO. They are a superb, albeit expensive, addition to the INCH. It is true that we could bring the price of the action down considerably if we used a different trigger, but the trigger and action are designed to be used as a system - not two items made to fit at some stage in the future (as some in Australia have found even at this early stage!). I notice you said "body and bolt" - all CG INCH actions come standard with the CG UNI trigger unit anyway.
Usually, any thoughts of pessimism about the claims for the CG UNI trigger go away shortly after the customer has used the unit!!
Camp Perry US National Matches general comment: The C.G-XTreme trigger has become the reference by which all the others are compared. Recent trips to the USA by the CG INCH manufacturers also showed the gaining momentum for interest in the CG XTreme UNI trigger.
The INCH uses a double register barrel tenon. The INCH is the only action with this feature. The idea of this being the threads cut on the barrel are not self centering, as the registers locate the barrel with the action bore axis, the thread only then having the job of tightening the barrel. Almost all other actions rely on the barrel thread to both locate the barrel concentrically and to tighten into the action body - this is not really a very good idea we believe.
The longer barrel shank is due to the shorter bolt travel from the rear located locking lugs. The system also allows barrel changes with no loss of zero.
One of the smallest, but biggest technical advances in the CG INCH, is that of the internal primary extraction. Action with a pin type bolt stop have a slot milled into the side of the bolt shank for a pin that stops the bolt from falling to the rear of the action - and provides a secondary safety that stops the bolt from being blown out the rear of the action and injuring the shooting (a la Rick Scoones).
The INCH goes further than this and has a cam built into the rear section of this slide, so that opening the bolt makes the slot act against the stop pin, giving close to 2mm of legitimate primary extraction, which is more than most. Almost all actions otherwise use extraction on the handle root - Barnard, RPA, Remington etc all have this feature. A softer material in the cross section (like 4340), cannot be used when dealing with high dragging forces like those in the primary extraction of the INCH.
Of course the CG INCH uses a narrow Sako style extractor. This is a very simple system (but not simple to make!!!) in use and function. There are only 3 parts, and none are pinned or screwed to the bolt in any way - being held in place by spring pressure alone. These small extractors are extremely strong, and very positive, having been machined to fit the case rim curve, not just milled straight like so many others.
Rod Shehan
Director
Woody Engineering PL ↑ Top of Page ↑
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