Frankenguns

Anything and everything related to firearm maintenance, modification, safety and troubleshooting can be posted here.

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User avatar
.270 WIN
Posts: 163
Joined: Fri Oct 23, 2015 2:14 am
Location: Mitcham, South London, England
PostPosted: Mon Apr 16, 2018 5:57 pm
Anyone who has read my posts knows that I like nothing more than modifying my guns, although I must say it is always to a purpose not for the looks! My club has christened some of my guns as Frankenguns and to be honest they are not the prettiest, but I now have them all functioning reliably and I enjoy competing with something that does not follow the crowd. I am sure that many of you modify your guns, whether for sport, HD or LE so I thought I would try and set the ball rolling and start a discussion with some before and after pictures and some brief descriptions of the modifications and the reasoning behind them. All my guns came out the way they did due to function, the form followed sometimes a few wrong turns and miscalculations. We in the UK are not so well served with parts and custom add-ons this side of the pond so needs must and the following are my creations. I did set myself some rules, I never interfere with the high pressure areas and with the exception of some gentle easing and smoothing, I will not file, cut or drill my guns. They can all be returned to stock configuration.
First, my least modified competition gun, and appropriately for this site, my high capacity Model 37.
Mod 37 s1.jpg
Mod 37 s1.jpg (12.73 KiB) Viewed 373 times

I bought this gun with the long mag tube already fitted, the lug had been moved to the end of the barrel to accommodate the 10 round tube. the tube was fashioned by cutting the existing threaded ends off a short tube and welding a plain tube to both. It was not a very good job and it took much careful easing and polishing to get it to work, plus a 40" wolff spring. A barrel clamp had been fitted which had partially crushed the mag tube and this was rectified by driving a round nosed aluminium rod carefully through the constriction. I found, in a friends box of bits, a M37 Black Warrior pistol grip stock ( I already had another pistol grip but more of that later) and a ringed Remington Fore-arm. The trusty Dremel took care of the Fore-arm internals and the wooden furniture was set aside for other needy cases and projects. An elasticated side saddle was put on the stock which also supports a raised soft cheek piece. The safety catch was made fully ambidextrous and rotates through 90 degrees instead of being push through. A home made light gathering tube foresight and a ghost tube rear take care of the sighting. I gently eased around the loading port to take away all the sharp edges and so as to permit a "load two" in competition, I've not yet successfully achieved a "quad load" with the 37 but loading is in the main much faster now. I sourced a new yoke and run the gun with the yoke hard against the mag nut to prevent loosening of the barrel (apparently a military fix, but all my 37's are so locked now, with far fewer fails than previously)
FG (6).JPG
FG (6).JPG (85.04 KiB) Viewed 373 times

One item that I developed when having all sorts of fail to extract, eject and cycle was my barrel locator device. When assembling my 37's, I leave the yoke loose, I slide my device along the top extractor slot and into the extractor cut-out in the barrel. This is a fairly tight, interference fit and ensures the barrel is perfectly aligned when I rotate the mag nut into the lug and then drive the yoke hard against the mag nut to complete the assembly process. It works for me!
This simple device (pictured below) was made from 5mm wide aluminium scrap, filed on the lower shaped end to 3.8mm wide
37 tool (2).JPG
37 tool (2).JPG (62.73 KiB) Viewed 373 times
User avatar
.270 WIN
Posts: 163
Joined: Fri Oct 23, 2015 2:14 am
Location: Mitcham, South London, England
PostPosted: Tue Apr 17, 2018 6:12 am
Valtro/Brixia PM5. This is a box fed, 7+1, pump action 12g. It is one of the simplest guns I have owned, with no carrier mechanism to raise the shells, the bolt, with a lug on the bottom simply strips a round from the all metal magazine and pushes it up a short feed ramp to chamber. Twin, solid action bars make everything rigid and the action cycle is positive and faultless. The gun appealed to me as a competition piece, improving reload times while staying with a simple pump action. Many of my peers use box fed auto's with the ammunition fussiness that seems to accompany these guns.
The PM5 has been around since the 80's, mainly as a military weapon suitable for guarding duty and marine operations. with its original short barrel and box magazine it enabled a higher capacity than a tube fed gun in the confines of ships etc. Also with the military requirement of constantly loading and unloading on duty shifts, the tube gun can eventually damage the ammunition. Recently, Remington and Mossberg have entered this field with their box fed pumps and there are some others around now too so maybe this type of shotgun will become more common and mainstream. One on my collecting wish list is the old Baikal MP133K, maybe when trade sanctions lift I shall seek one out!
Valtro Brixia.jpg
Valtro Brixia.jpg (31.42 KiB) Viewed 368 times

Firing this gun confirmed that it was what I was looking for, unfortunately, I found that magazine changing was slow due to the 'rock and lock' format (AK) of the magazine retention system. Also, the magazine capacity was on the low side for serious competition. My first modifications were to the magazines themselves, with various extensions and failures until I settled on the Cactus Arms 2 round extender box which, with a slight modification, fitted firmly on the original magazine. Although only a 2 round increase, it meant that in functioning, only the follower entered the extension and the original spring could be used. this gave me reliability and a 9 + 1 start load.
I went through many weeks and months of trying to get quick with the mag change, but it was apparent that from a military perspective this system was ideal, solid, locked and reliable, with sufficient rounds for its stated purpose, for competition it was not so good. If you ask any IPSC shooter or 3 gunner, I am fairly certain they will say that matches are won and lost on the reloads! I eventually realised that I would have to re-engineer the magazine system for what I needed. After many false starts and fails I realised that a full mag well was the only option, there was nothing on the market so I needed to fabricate. I made the front 'wall' of the well from aluminium block, carved to incorporate a new polished feed ramp in one piece, locked into the original lug location and pinned with a 5mm allen bolt and locknut. The rear 'wall' was pinned at the original mag release point in front of the trigger guard. the side walls were screwed to these substantial front and rears. This gave me a rock solid all aluminium magazine well. The original locking lugs now became 'stops' to put the magazine in the correct place for reliable feeding. Retention was achieved by mounting an oversize 'slap' type spring loaded catch on the left of the well, this engages a brass block screwed to each magazine through one of the side peep holes (again to avoid drilling etc) This gave a positive, straight in to lock up feed and the mag falls out when released. I added a linkage to the release to also enable right hand trigger finger magazine ejection and because I was looking for total reliability, I added a spring loaded 6mm ball detent on the right side of the well which also engages one of the peep holes and adds to the positioning, locating and retention of the magazine. This does not affect release as it is, on its own unable to hold the mag when the catch is operated. Somewhat over-engineered perhaps, but it is now super reliable, slick and fast and when inserting a magazine there is a satisfying solid click that informs you that all is in place.
FG (1).JPG
FG (1).JPG (115.29 KiB) Viewed 368 times

Another area that I needed to look at was sighting, I needed fast acquisition, the ability to move around with the gun in the shoulder (for room clearance etc) and again simplicity and reliability. My eyesight is not what it was and I am right handed with a left master eye. After many attempts, fails and disappointments, I eventually conceived what I call 'binocular' sights. This is a pair of fairly low cost dot sights, one green dot and one red dot with the red dot mounted on the weaver rail and the green dot offset to the left. It may seem a little clumsy, but in practice it works perfectly, with both eyes open I have full peripheral vision and what is presented to me is a sharp green dot within a hazy red dot. For left (weak) handed shooting I simply see the sharp red dot with my better eye. My performance and times recorded really show a vast improvement.
FG (2).JPG
FG (2).JPG (106.79 KiB) Viewed 368 times

Other additions are a laser (for smoky, dusty or misty conditions) which can out-focus to become a usable green flashlight mounted under barrel and switched from the fore-end just in front of the rail mounted, angled fore-end grip. This particular fore-grip serves two purposes. firstly, it gives great purchase on manipulating the action and secondly it allows the fore-grip position to be moved a little rearwards to counter the effects of the longer receiver required by the magazine type operation. For me also, the balance, even fully loaded is just about right.
Finally, an elasticated shell holder on the stock for those 'match saver' shells (with no mag fitted the gun can be easily single loaded)
It may look a touch ugly but it performs well as long as I do my bit
User avatar
.270 WIN
Posts: 163
Joined: Fri Oct 23, 2015 2:14 am
Location: Mitcham, South London, England
PostPosted: Fri Apr 20, 2018 7:27 am
Remington 1187 Left hander
Another class that I shoot in is 'Standard' sometimes known as 'Modified' This class permits self loaders, but no box magazines or electronic or optical sights (hi-vis light gatherers are permitted though) This class is dominated by Benelli and Beretta with their fine auto loaders. Many years ago in the infancy of PSG in the UK I graduated from a Franchi SPAS 12 (not very competitive) to a fairly standard Remington 1100 which served me well for many years. Foolishly selling when I was offered a good price! Anyway, to compete in 'Standard' I did not want to invest £1500 in one of the Italian guns so picked up an 1187 which was looking a bit sorry for itself (and was not UK magazine restricted) I already owned a restricted 1187 Lefty so was quite confident with the brand and my familiarity with it.
This is my restricted 1187 as a 'before' picture, (the wood has been Danish oil refinished on this one)
1187t or t (5).JPG
1187t or t (5).JPG (64.89 KiB) Viewed 347 times

In order to compete, I needed some modifications (as always!!) The class rules state 8 rounds maximum loading at the start of each stage, and unlimited once a shot has been fired. I had in my box of bits a short extension tube but that only gave me 6 + 1, I also had an old Savage magazine tube. I re-profiled the Savage end cap, trimmed the Remington extension then put the two together, using half of the old Savage forend tube as a sleeve (that old broken Savage always had a sticky action so I got a reasonably tight fit!) Add a little epoxy and I had a super long extension. I had considered cutting it to the muzzle length but decided that one or two rounds more could have benefits, and anyway many of the Italian guns have stupid length mag tubes. This magazine extension makes the gun 11+1. I added a mag tube clamp for security/anti rotation. I polished the internals of my magazine tube and added a Wolff 40" spring. I have ordered a comp/low friction follower even though the original seems up to the job anyway.
I purchased a Dave's Metal Works Easiloader and Bobbin type speed charging handle, fitting the Easiloader was fiddly but not especially so, only the minor adjustment to the trip point is s bit frustrating as its in and out of the gun between filings. I eased and polished the loading port, adding a small aluminium ramp that sits between the fingers of the Easiloader as I found that when loading two in tandem, the second round occasionally caught the squared off top part of the mag tube end.(I did not want to file this part as it is fundamental to the operation of the gun)
I already had a Monte Carlo synthetic stock (that fits me well and puts my head in the right place!) which came off my auction bought 870 and a synthetic fore-end. I eased the fore-end around the loading port. I fitted a rail to the underside of the fore-end and mounted an angled fore grip, I am a great fan of these and will eventually fit one to my M37. They give great purchase and control and also eliminate the need for 'muscle memory' when taking control of the firearm.
To the stock I added a grip enhancer, which basically gives a finger groove grip and moves the hand slightly closer to the trigger, more like a full pistol grip. It is very comfortable and whilst it is a right-handed addition, it does not adversely affect the grip when shooting left or weak handed. It comes with a thumb rest and I am undecided about that for now, I shall see how I get on with it and then decide whether to file it off. I added an elasticated shell holder
FG (5).JPG
FG (5).JPG (81.43 KiB) Viewed 347 times

I modified the safety catch to the same pattern I used on my M37, 90 degrees of rotation, forward to fire and down for safe. My reasoning is that my ambidextrous safety will be common to all my competition guns, The Valtro PM5 is next for that modification.
Just forward of the ejection port I fitted a 'match saver' single round clip made from a Prodec belt clip. One of the reasons that I like a left handed gun despite being right handed is the seeming ease of loading/jam clearing that having the ejection port on the left seems to give. I never see the cases eject across my line of vision (which is what many people seem to say/fear) Maybe its just me, but keeping control of the gun in my right hand whilst loading and clearing with my left, checking, proving safe etc by just rotating the gun a quarter turn to the right seems more natural?
I fitted another of my light tubes up front (in yellow as an experiment) and a 'ghost tube' on the rib as a rear sight/guide. I will run this gun full choke for now but also have imp mod as an option. I will have to buy a cylinder choke for slug, but we don't shoot slug that often.
This gun has cost very little and seems to work just fine, with bits from here and there it really is a Frankengun. My wife thinks it should be 'Bat-gun' with all the curves and shapes
FG (4).JPG
FG (4).JPG (83.08 KiB) Viewed 347 times
User avatar
.270 WIN
Posts: 163
Joined: Fri Oct 23, 2015 2:14 am
Location: Mitcham, South London, England
PostPosted: Fri May 18, 2018 7:11 pm
A bit of an update to the above, the M37 now has an angled fore grip, mounted on a rail fixed to a slightly squarer fore-end that I had spare. The ringed fore-end is now on my '65 M37. Handling is improved (in my opinion) and the gun comes to the shoulder with a satisfying familiarity.
37afg (4).JPG
37afg (4).JPG (96.01 KiB) Viewed 237 times

The 1187 has developed a slight reliability problem with regards to cycling. I have installed a new gas ring and shortened the mag tube. Hopefully, the next trip to the range will show some improvement. I also moved the angled fore-grip forward as it was fouling my speed-loads (also its a better shooting position) This gun really loads fast now and when shooting reliably, its an absolute peach.
rem1187comp (2).JPG
rem1187comp (2).JPG (92.24 KiB) Viewed 237 times

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