Friday, February 2, 2007

Arnett Patent System Grizzly Technology History

At the time when LAR Mfg. Co. was manufacturing the first batch of pre-production prototype Grizzly Pistols for me under License, we needed barrels for them.

I was then serving as an in-plant Consultant to LAR (since I had invented the technology and licensed it to them), and I had the most complete knowledge of what the desired end result was to be. I suggested to 'Robbie' that he order barrel forgings from Crucible or Carpenter [if I recall correctly] since they were the only barrel forging available that were made of "4150GM" (Government Modified) steel - the strongest barrel steel then affordably available for the purpose - with a "grain size Five or finer".

He didn't really know if the gun would sell, so apparently to hedge his risk, he got some .45 caliber Douglas rifle barrel blanks from which about six (?) Grizzly Pistol barrels were made. They were properly dimensioned and heat-treated, so far as I am aware.

We were testing one of the first batch of commercial Grizzly Pistols made, to see if, and when it would destroy itself from just being fired. We had put about ~5,000(?) factory WW 45 Win Mag loads through it and saw no dimensional or other changes in the firearm, so we decided to try some WW 45 WIN Mag Proof loads. Just a couple was not enough!

I had suggested a design for a Lexan polycarbonate automatic proof-firing chamber that held the gun so it could be fired safely by an operator from outside the box. They built one and we began the test.

At about the ~1,200th(?) Proof round fired through that one pistol, the gun jammed with the slide retracted partially frozen in that position, the brass was intact, everything else was fine. Upon examination, I found that the barrel had split longitudinally! I inspected the situation and disassembled the gun. I took photos. Nothing was wrong with the remainder of the pistol in any way.

The split barrel was sent to a testing lab in SLC who determined that the barrel steel had (if I recall correctly) "between 0.10 and 0.12 points Sulfur" in it. I still have the split barrel, the lab report, and the photos in my papers.

As most gunsmiths know, some barrel makers use "re-sulfurized" barrel steel to make them easier to machine. But the higher than usual sulfur content also makes them slightly less strong than a barrel made with less sulfur (i.e. 0.02 - 0.05 points). When used in a rifle barrel, with a normal large "pressure-reinforce" area over, and ahead of the chamber, they are plenty safe and work fine. But when turned down to the dimensions of the Grizzly pistol barrel, heat-treated to a very hard condition, then subjected to the firing impact of ~5,000 commercial 45 Win Mag loads, and ~1,200 45 Win Mag Proof loads, under high, repeated impact, the high sulfur content can cause crystallization, and the barrel may split. [I have all the exact numbers in my Log books which are in storage, so I'm giving you 'best recollections' here]

That prompted LAR to order the forged barrel blanks(!), and there was never another incident of that type - so far as I am aware.

None of THOSE barrels were ever supposed to be shipped, obviously. However, I suppose it's possible that someone who didn't know any better may have put the remainder of those barrels with other parts and sold them as firearms. I don't know.

If you want, if you have a split barrel, you could send it to a testing lab and have them analyze the steel. If the sulfur content is high, then it may be one of those barrels.

Hope this helps.

Perry Arnett - sole conceiver, designer, inventor, patent holder (#4,253,377), engineer, and licensor of the Grizzly Multi-caliber Magnum Semiautomatic Pistol and its Arnett Patent System Multi-caliber Conversion Units, and other related technologies.

If I may be allowed to set some of the record straight here, since there seems to be some confusion about some of this:

I solely conceived the conception, - that is, the conception of using the "Browning Lock" (as embodied in the 1911-A1 pistol), to create a Multi-caliber, Semiautomatic Magnum Pistol that would safely contain the pressures and forces in the 45 Win Mag, and other major magnum caliber cartridges, and to turn that conception into a firearm that could be affordably made, and sold at a price that would allow others to enjoy that firearm;

- since my first patent for Multi-caliber Conversions (#4,253,377) had already just issued, this conception of the Grizzly Pistol, and the resulting technology, and the products resulting therefrom, were ALREADY COVERED under my patent at the moment of their conception!;

- I performed the math and physics analyses, the strength of materials, I hand-built the first fully functioning prototype Grizzly Multi-caliber Magnum Pistol (#PP001), and I hand-held-fired the first prototype in my own hand;

- I determined the materials, and heat treatments required; designed, engineered and specified the fits, finishes and tolerances; sizes, shapes, features, contours, appearance, ergonomics, function, name, etc., for the production products;

- I drafted the patent application, filed the patent application through my patent attorney [M. Wayne Western], and was awarded the patent (#4,253,377);

- I directed the taking of the first Grizzly product brochure photos for North American Manufacturing Co. at a guy's house in Provo, Utah, AND the subsequent photos for LAR - which were done under my direction by Tim Hatfield, a professional photographer, behind a barber shop, outside, in Cedar City, Utah;

- I personally wrote ALL the Grizzly and Multi-caliber Conversion Unit product brochure text and verbiage, and all of the Grizzly Owner's Manual; I personally edited all the text, and whatever errors of grammar or syntax there are, are mine! My friend, Dennis Rowley, helped with the layout of those first brochures, and he did the layout of the draft Owners Manual largely by himself.

- the Grizzly Logo [the raging bear] was designed at MY request, by a college art student then attending SUU in Cedar City, and was licensed by me to LAR as part of the Technology Transfer License Agreement package;

- the 'Grizzly' trademark, (even though filed by LAR), is owned by me, as it was also transferred to LAR from me as a part of the Technology Transfer License Agreement package;

- I showed the Grizzly Magnum Pistol and Multi-caliber Conversion Units at various gun shows; took ~$300,000 worth of orders for it and Conversion Units from Ellet Bros. ALONE, in 1981(?), at the NASGW show in Denver; I still have their green computer fan fold printouts...

- I initially licensed the technology to North American Manufacturing Co. in Spanish Fork, Utah, [owner, Frank Talley], who, after about six months, was cordial enough to return the License, since they were then engaged with new military projects, and were unable to proceed further with it at a pace he and I thought it deserved;

- So, in a conversation with my then tax attorney [Jim Arrowsmith], who happened to also be the tax attorney for LAR, he introduced us, and I consummated a Technology Transfer License Agreement with LAR Mfg. Co. of West Jordan, Utah. I then worked with them at their request, in their plant, for about 14 months as an Inventor/Manufacturing Consultant on the manufacturing and marketing of the Grizzly Pistol Technology Licensed Project.

In my 2,500 volume technical library and other papers, I have all the original engineering calculations and bent corners and highlighting on engineering texts.

My signature is on the patent. The patent is issued to me as "Sole Inventor".

My signature is on the first Technology Transfer License Agreement with NAM Co., and on the second with LAR.

My signature is on all the ~50 or so, Machine Drawings for Grizzly Magnum Pistols and Multi-caliber Conversion Unit parts - in all their variations [through about 1986].

My signature is on all the Manufacturing Change Orders issued from inception through about 1986.

My signature is on the [few] royalty and License Fee check (copies) I was paid and cashed.

More than 50 of my friends, neighbors and family were around during the time I invented the Grizzly Pistol and its Multi-caliber Conversion Units; lots of others in the gun business: Herm Bockstruck of WW (deceased?), Terry Paul, Jeff Talley, Harry Wind, Peggy Stein, Dean Grennell, Bob Milek (deceased), the nice folks at Ellet Brothers, Golden State Castings in Ogden, Utah, etc.; my oldest son, Aaron, who was the second person to fire the 9mm Win Mag prototype Conversion Unit - when he was about 10!

Those who know, KNOW...! The rest is history (or garbage...).

I'm pleased to see and hear about all the folks who like the Grizzly!

I did my damnedest to make the Grizzly Interchangeable, Magnum Multi-caliber Semiautomatic Pistol the finest big bore handgun ever produced. (You would never believe how much time I spent doing the math, revising, and re-revising the tolerance-stacks on the manufacturing drawings so that:

a) the relevant parts would fit together as tightly, smoothly, and as accurately as possible, thereby giving out-of- the-box, match grade accuracy, while,

b) being able to be manufactured at a cost that would be acceptable, affordable and profitable - so that ANY slide made could be mated to ANY receiver made and ANY barrel and ANY bushing, and the resulting accuracy would be Match-grade! - WITHOUT ANY hand fitting [I DID THAT!] - and that the proper materials selection, and proper heat-treatment of those materials would allow these parts to retain that high quality fit, essentially, forever.

These were all done on an HP 41CX hand-held calculator, (remembering that this was before cheap computers and electronic spreadsheets were common in manufacturing plants.)

I only hold two patents (self-funded), but the Grizzly Multi-caliber Pistol technology is but one of the more than 300 OTHER new product and process inventions I've conceived, designed and/or built since I was 17.

I've owned a small company specializing in new product development and innovative machine design for factory automation since 1985. Now I do a bit of free-lance machine design, manufacturing consulting, and lots of inventing....

FWIW: I have a 37 page Enabling Patent Disclosure for a new technology and series of products I call "The Last Rifle Technology" - since it embodies ALL the features which, if one owned THIS rifle, he'd never have to, nor want to own another; - the key aspect of which is that all 'variables' that might cause a miss at extreme range are 'digitally compensated for', thus insuring first round hits that might otherwise not be able to be taken.

Probable military contracts possible; serious inquires invited.

Sorry for the length. Thanks!

Perry Arnett


imnak said...

This is very interesting!
If I am following you correctly you fired 1200 proof loads through the douglas barrels.
How many proof loads did you fire through the forged barrels?
Thankyou for your time

Kyle said...

I am in the process of buying a 45 win mag LAR Grizzly. The problem is that I can't because it doesn't come with a magazine. Can someone please tell me were I can get my hands one? Please email me tcsnake[at]

Kyle said...

I am in the process of buying a 45 win mag LAR Grizzly. The problem is that I can't because it doesn't come with a magazine. Can someone please tell me were I can get my hands one? Please email me tcsnake[at]

Bradley D said...

One can scour the Internet and this is the only place I see any documentation about the "Inside Story" on the Grizzly Win Mag.

Amazing. There is definately some reading 'between the lines' where this behemoth is concerned.

LAR Tells me that my Mark I was manufactured on 05 Feb 1990

The ammo is all but impossible to aquire nowadays, but in our shop here at we offer custom reloads - of which the 45 Win Mag is a very popular caliber.

Ordos Incorporated said...

Want to buy rights to manufacture the grizzly LAR.

grizzly44mag13 said...

I currently own a Grizzly Mark IV 44mag. I also recently purchased the Luepold Deltap0int Pro
red dot sighting system with the multi-pistol mounting kit. However none of the included dovetails seem to match up with the dovetail on the Millet target sights that came standard on the Grizzly MARK IV.

Does anyone know which dove tail style is on the Mark IV?

Any suggestions for a gunsmith in the midwest that would be capable of doing a nice custom mount if required. I'm located in Iowas