Rockwell Hardness – Forged vs. Casted Parts
Unlike other gunsmiths, MCP does not rely on buying our components from some other manufacturer with no knowledge of their quality control except of what they publicly advertise. In the MCP shop, we start with a solid billet of 4140 hammer forged steel at Rockwell Hardness (RC) of 35. Other manufacturers usually start with very soft cast steel billets at RC of 18 to 22. This way, they can save a lot of money on the cutters which are used in the CNC process. Afterwards, they send the finished product to be heat treated to a surface RC of 28 to 40. The reality is that this hardness is only superficial and does not penetrate to the core of the metal (it is 0.002 to less than 0.010 inches thick). The chemical reason as to why heat treatment strengthens metals superficially is very simple; heat rearranges the geometry of molecules of metal so that molecules can potentially get much closer to one another. The tighter packed molecules significantly increase the strength required in order to separate them from each other. During this molecular rearrangement, surface rearrangement also takes place by as much as 0.001 to 0.002 of an inch, and this secondary “rearrangement” is better known as surface distortion (or warping).
Typically, the gunsmith receives the final heat treated product, which is an oversized frame and slide. This means that before our competition can do any accurate measurements, they need to remove the surface distortion (warping) created by heat treatment process. This means they basically remove as much as two to three thousands from the frame rails as well as from the slide rails. Then they need to remove an additional two to four thousands from each side of the rails to be able to fit the frame to the slide. The problem is that heat treating is a superficial process with maximum depth of 10 thousands of an inch! So now you just need to do a little math: Add the surface distortion that the gunsmith removes plus the oversize frame to slide correction, and now you have at best, a surface which is less than two thousands thick, and at a level of about RC35. Underneath this surface lays the original foundry hardness of RC18 to 22. You do not need to be a metallurgist, or rocket scientist, to know that this thin surface over a short period of time will simply ware out and result in more distortions to the surface of the frame/slide. Surface distortions are what cause a loss of tolerance at all levels: slide/frame mating, barrel lockup, bolt face and barrel hood wear, etc., resulting together in a significant loss of accuracy.
What happens if you started with forged billet of steel with a RC of 35 like MCP?
The answer is that not much happens when you send the finished product to be heat treated to the RC40. Due to the fact that it does not require as much heat treatment as if you were changing from RC18 to RC40, you end up with surface distortions (warping) are zero to less than 0.0001 thousands. Of course, we recently begun a new chemical heat treatment process that reduces this to ZERO, but it’s still important to understand that MCP starts off with high qualify FORGED steel.
Why don’t other manufactures start with metals at RC35?
Very simple, it is much harder to shape and cut a forged metal billet at RC35 than it is to cut a cast metal billet at a RC of 18. You will need to replace your cutters more often and that translates to a lot of money. At RC35, it takes $19350.00 of cutters for manufacturing of 50 slides and frames. It translates into $387.00 added cost to each slide and frame. Now if MCP started at RC18, we could manufacture over 200 slides and frames before we need to change our cutters out. However, most manufactures do not change their cutters, they simply re-sharpen them. Of course, you do lose accuracy when the original tolerances of these cutters are compared to the factory purchased cutters, which translates into loss of tolerances in our competition’s final products. But who cares, they make it up to you in price, right? That’s somewhat correct, but the reality is that you get what you pay for. Out of the MCP machine shop, slide/frame number 001 will have the same tolerances as slide/frame number 1000.
Finish and Chemical Heat Treating
uses a matte black finish on our pistols that produces a beautiful
firearm, reduces friction, and increases the Rockwell Hardness to RC70!
This has a HUGE impact on the accurate life of the pistol. At this time
we are sending out parts that start at a Rockwell Hardness of RC35 and
effectively doubling them to an RC70.
Additionally, this process is applied to ALL steal parts of the pistol INCLUDING the interior of the barrel and the chamber. This results in a barrel that is extremely easy to clean and that we have yet to see foul.
One other interesting aspect of this new process is that it doesn’t cause any type of surface distorion (explained in the section above). As such, while the metal turns black and the hardness increases to RC70, the parts come back from the chemical process exactly the same as when they left the shop… except they are really hard and they’re black.
The most important part of the firearm is the barrel. A firearm only shoots as well as the barrel. The biggest assumption that MCP hears all the time is that barrel manufactures test their barrels. We find that this is NOT the case. We have had many instances of barrels from highly reputable companies not shooting well. At MCP we put EVERY barrel in a barrel tester to see how a barrel groups at 50 yards. Additionally, we look for “fliers,” bullets that leave the grouping. If a barrel consistently has fliers, then we send the barrel back to the manufacturer. We use our own ammunition to test all barrels MCP uses to assemble it’s pistols, and MCP rejects any barrel that does not group under 1.5 inches at 50 yards.
We typically keep 9 out of 10 barrels; we have a rejection rate of about 10% of the barrels that we test.
The second most important aspect of ANY pistol is barrel lockup. This is accomplished by properly cutting the bottom barrel lug, the bushing, the bolt face / barrel hood surfaces, and ensuring the barrel lugs are machined flawlessly to match the slide stop. At MCP we find that honing compound does not work for any of part of these manufacturing processes. The parts MUST be precision cut using CNC milling machines, lathes, and surface grinders. We don’t leave the manufacturing and quality of your pistol to chance.
To accomplish final fitting MCP assembles the slide, barrel, and bushing, then cuts the lower barrel lug WHILE THE SLIDE / BARREL combination is locked in place. This ensures that the lower barrel lug is in perfect alignment when the slide stop.
The lower barrel lug is cut to within a tolerance (0.0002) thousands of an inch! Most armorers spend hours using Dykem (machinist Prussian blue) with various honing compounds, files, and sanding tools to perform the cutting of the lower barrel lug, usually with poor results. In our experience nothing beats using a CNC milling machine for this process.
Chambering can NOT be done effectively by hand. Period.
Chambering is a three dimensional process that requires precision. The only way to properly ream a barrel is to use a lathe or CNC lathe. At MCP we use reamers that are specifically designed for us and enable our pistols to shoot consistently and operate flawlessly.
MCP fits all of our triggers using CNC surface grinders to ensure the tolerances are consistent. We offer triggers in various lengths, such as medium, short, etc.
Our sears are cut using a CNC surface grinder that cuts them to the exact angle we require.
MCP has recently started using a chemical heat treating process that increases the Rockwell Hardness of all of the steel parts of our pistols to an RC of 70.
GREATLY increases the durability of our pistols. Current testing shows
that customers should be able to get over 10,000 rounds through their
MCP pistol without any significant wear to any part of the pistol. At
this time we do not believe that our current models of 1911 pistols will
actually show any signs of wear in under 50,000 rounds.
However, eventually, you will have to replace a part. MCP makes ALL of our pistols to be as close to identical as possible, while still maintaining the tightest of tolerances and producing a functional firearm.
We also keep a COMPLETE RECORD of the MAJOR COMPONENTS and the measurements of EVERY pistol we manufacture. So this means that for simple items, such as a barrel bushing, we can manufacture you’re a new one and drop it in the mail.
Some replacement parts, such as a new barrel, would require you to send the pistol to MCP.
orders for replacement parts are a result of damaged caused by poor
maintenance or, more typically, accidents. MCP will do whatever we can
to get you shooting again as quickly as possible.