Weak M 71 Browning hammer springs

Old Bear · Post by **Old Bear** » Sat Sep 08, 2007 2:04 pm

Has anyone out there had reliability problems with the Browning M 71 mainspring not snapping the primers 100%?
I have one converted to 450 Alaskan and find that the coil spring is downright wimpy. I got this thing for brown bear and don't dare use it like it is.
Would like to find some very good photos of the flat mainspring in the originals so I could fabricate one.

Also: anyone have some good load data other than what's currently on the net for the 405 grain jacketed bullets? www.loaddata and www.ammoguide.com don't cover the round very comprehensively or they mostly cover cast bullets.

My 450 has the long magazine which hold 7 rounds and functions very smooth. Recoil is stout with the 405 grain Remington bullets backed up by 67 grains of IMR 3031, but not unmanageable. It's good enough to keep me invested in making it 100% reliable.

I have built traditional muzzle loaders for over 35 years so would have no trouble coming up with a flat mainspring set up. Just would love to have some good photos to go by. I don't have access to one for a hands on so photos will have to do.
Thanks
Old Bear on Kodiak Island
PS: Yes I have both a .338 and a 375 H&H but the big lever gun is what I want to use more than both of the other put together.

WinM71 · Post by **WinM71** » Sat Sep 08, 2007 2:36 pm

You mention the "flat mainspring in the originals". The original Winchester M71 had the coil mainspring, it was seen as one of the significant improvements from the M86 design with its leaf mainspring.

Mike D. · Post by **Mike D.** » Sat Sep 08, 2007 3:28 pm

The Browning coil mainsprings are very reliable and have excellent tension. Perhaps someone weakened the spring. I bought a couple extras to use in my Miroku Winchester 1886s.

Old Bear · Post by **Old Bear** » Sat Sep 08, 2007 3:36 pm

Well, there you go. Shows you how much I know!

The coil mainspring in my 71 just will not get the job done. It even looks wimpy! Is there no way to improve this?

Are the Browning copies the very same as the Winchester's? Can I find and original Winchester coil and not the Browning make?
It appears from some of the poorly rendered drawings I have been able to find on the net that Browning changed the trigger mechanism and lever lock (nomenclature?). The Winchester trigger looks like it was one piece while the browning is two pieces with a couple of small coil springs in the mix.

I bought some coil spring stock from Brownells and made a one piece spring pin with longer coil. Made it so that it just makes complete compression at full cock but still will only pop 18 or so rounds with one hammer fall, out of 20 rounds.
I am using CCI primers which I have heard are harder than some other makes but that should not be a factor here. They are also new fresh primers.
I have to find a solution to this problem.
Perhaps I was thinking of the 86 Winchesters? And perhaps modifying the M 71 back to a stout flat mainspring would not be all that bad of an idea?
I do not have this rifle as a collectible but as a working gun for Kodiak Brown Bears.
ANY help is appreciated and as I have already demonstrated I sure don't know that much about the internals of these rifles.
Old Bear

Old Bear · Post by **Old Bear** » Sat Sep 08, 2007 3:40 pm

Mike,
Where did you get your mainsprings from?
Thanks
Old Bear

BigSky56 · Post by **BigSky56** » Mon Sep 10, 2007 12:19 am

Old Bear, you can get brng rifle parts at Midwestgunworks.com
You might also check your firing pin spring and firing pin? danny

Leverluver · Post by **Leverluver** » Mon Sep 10, 2007 1:15 am

Old Bear

Don't feel like the Lone Ranger; mine also has a pretty weak spring in comparison to other Brownings, and no it was never altered, (for those that wonder). I've seen several Browning 71s with very mild springs. Even though they are mild, they always have set the primers off. Your's is obviously a little too mild. The B71 springs weren't anywhere near as stout as the ones that come on the 86s, even the first (non-rebound) Browning 86 (which I also have) and, when cmpared to the 71, it feels like the suspension spring off the rear of a 52 Buick.

Mike

Mike D. · Post by **Mike D.** » Mon Sep 10, 2007 10:02 am

Old Bear wrote:Well, there you go. Shows you how much I know!

The Winchester trigger looks like it was one piece while the browning is two pieces with a couple of small coil springs in the mix.

Old Bear

Quite the opposite is true. The Winchester trigger/sear assembly is the two piece with small spring and plunger design and the Browning is a one piece trigger and sear.

I bought my small parts from Midwest Gun Works. Kind of expensive, but the only place to get 'em.

Old Bear · Post by **Old Bear** » Mon Sep 10, 2007 1:27 pm

Winchester two piece trigger -
The barrel on this rifle is obviously a replacement with only 450 Alaskan stamped on it. The action only has a ten figure number in two rows one over the other. The second row is PR1B7.
The guy I got this rifle from did not know much about it. I am now assuming it was assembled from various parts.
I appreciate what I am learning here. Some of the parts appear to be stainless steel. Other than the main spring the action works smooth as silk and the 450 cartridges feed and extract perfectly.
The wood is very plain.
Thanks for all the input - would be interesting to know if this is a true Winchester action or something cobbled together with a mix of Winchester and browning parts.
Old Bear

Mike D. · Post by **Mike D.** » Mon Sep 10, 2007 2:56 pm

My gun is a Winchester action, but reassembled with some Browning parts. It has a Browning trigger and spring and hammer. The Winchester mainspring and fork was retained with the rebounding portion of the fork removed. The fork was rounded and polished to give a smooth and positive feel. You can see that it fits into the rear of the hammer, not on the side like the rebounding hammer did.

The Browning trigger and hammer fit perfectly into the Winchester ELW and provide a positive half cock like the original 1886s have.

My gun has been fitted with a full magazine, the tang safety removed and the slot filled. It has been remarked as original lightweight 1886s were at the beginning of the 20th C.

Cimarron Red · Post by **Cimarron Red** » Mon Sep 10, 2007 7:05 pm

It's been some time since I had my Browning 86's apart, and I may be mixing them up with my Miroku Winchester 86. But about 6 or 7 years ago the Winchester began to misfire. After investihating the situation, I discovered that the firing pin return spring had collapsed (why I can't imagine), and the spring was slowing the firing spring strike. Ordered a new spring, and all is well.

Mike D. · Post by **Mike D.** » Mon Sep 10, 2007 7:57 pm

Cimarron Red, that is the only piece I have not been able to remove from my gun. For some reason, the roll pin that holds the firing pin assembly will not drift from the bolt.

I just might replace the entire bolt with an original one from a 1920s '86, IF it will fit without too much hassle.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 5:57 am

Mike D.

Too bad that pin won't budge. Before you take drastic measures, I'll check to see if I have an exploded drawing of the Browning just to confirm there is a spring in there. I know for sure there's one in the Winchester version.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 7:44 am

Mike D.,

I found my diagrams of the Browning 86 and the 71 along with the 53, 65 and B-92. They all have the trigger return spring. Also, all but the B-92 have an inertia firing pin (as do the Miroku Winchesters.)

To quote from the Browning manual, "The Browning Model 71 has an inertia style firing pin with an internal locking system that is locked to the rear until struck by a forceful blow from the hammer." My assumption is that this is to prevent the firing pin from contacting the primer if the bolt is slammed home vigorously. This seems unlikely to produce an accidental discharge, but lawyers will have their way.

The inertia firing pin consists of 6 parts -- the firing pin proper; firing pin inertia slide; firing pin inertia slide pin; firing pin inertia slide spring; firing pin safety lock. There may be a problem with this mechanism -- the spring, perhaps -- that is causing a weak hammer blow to be transmitted to the firing pin proper. Of course, you've probably already checked this out.

Let us know what you find.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 7:48 am

I should have addressed my responses to Old Bear as well. My apologies.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 9:06 am

I have the exploded drawing of the Browning 1886 and it does have all those silly parts to the firing pin mechanism.

So far, I haven't been able to disassemble the Winchester/Miroku firing pin assembly. I probably will not until I get my hands on a pistol grip lever and change the lower tang and buttstock to a PG style.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 11:35 am

Mike,

Do you have a line on the parts and on the pg stock for the conversion?

Also, you might try freezing that bolt assembly. This might provide enough shrinkage to allow the cross pin to be drifted out.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 11:38 am

Red,

I have everything but the lever. Winchester will not sell a PG lever to anyone but a "certified" gunsmith, but they will sell the straight one to anybody. Go figure. I have had zero luck in finding a loose PG lever.

Leverluver · Post by **Leverluver** » Tue Sep 11, 2007 11:40 am

"Also, all but the B-92 have an inertia firing pin (as do the Miroku Winchesters.)"

Besides the 92 (before our colleges cranked out too many lawyers) the Browning 95 also does not have an inertia firing pin.

"My assumption is that this is to prevent the firing pin from contacting the primer if the bolt is slammed home vigorously."

Try this little test; prime an empty case and chamber it and then smack the hammer with a plastic mallet. You cannot make the cartridge fire. In fact, you could throw a loaded Browning 86 or 71 off a cliff and they could land on the hammer and they would not fire. Try that with an original set on half cock.

I personally like a simple inertia firing pin. Although they did go crazy overboard with firing pin mechanism on the later Win/Miroku 95s. That goofy thing has more parts in it than my car engine.

Rimfire McNutjob · Post by **Rimfire McNutjob** » Tue Sep 11, 2007 12:37 pm

Mike D., will one of the PG levers from an original 71 work? There are two of them up on GunBroker at the moment for $30.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 12:49 pm

Rimfire McNutjob wrote:Mike D., will one of the PG levers from an original 71 work? There are two of them up on GunBroker at the moment for $30.

Good question, RMcN. I have a couple of original 71s but never thought of those levers. I do know that the trigger and sear will not fit the newer guns because I tried that route.

I'll look on GB in a few minutes. Thanks for the heads up.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 1:28 pm

Mike,

Try these guys. I've bought Browning parts from them some time ago. They're located in Alberta, Canada.

http://www.westerngunparts.com/

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 1:31 pm

Correction: I've bought both Browning and Winchester parts for Miroku-produced guns from this company. In fact I need a part for the model 53 and I'll be giving them a call this week.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 2:15 pm

Thanks Red, I emailed them my request.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 2:57 pm

Mike,

I just phoned Western and ordered a part for the mod. 53. They have it, and it wil be on its way to me tomorrow.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 3:52 pm

They do have the PG levers. $129.95 US plus S&H. Yikes! I'm gonna go for it though; it's likely my only chance to score one.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 4:09 pm

YEAH!! I just phoned WGP and the lever is on the way. Thanks, Red. Now, I'll be able to complete the project to my satisfaction.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 4:33 pm

Mike D.,

You're surely welcome! That's a worthy project you've undertaken. I've often thought of converting my Browning 86 rifle to a pg configuration. I'm not certain that the Miroku/Winchester pg tang will be compatible with the Browning. If I could overcome my sloth, I'd take both my guns apart side by side and determine the level of compatibility.

Where did you get your pg stock, Mike?

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 4:38 pm

Hey, Mike,

The bite may not be quite so bad. I believe they quote Canadian prices and then do the conversion at the time your card is charged. I admit, though, that I'm not certain of this.

Mike D. · Post by **Mike D.** » Tue Sep 11, 2007 6:54 pm

The tangs are interchangeable, Red. The PG tang differs only in that it is thicker to accommodate the curve of the lever.

Here is the straight tang and Browning parts to replace the Winchester rebounding hammer.

This is the PG lower tang.

The wood I have is from Treebone Carving. I will take photos of the project during the finishing process.

Cimarron Red · Post by **Cimarron Red** » Tue Sep 11, 2007 7:18 pm

Thanks, Mike. I thought there might some differences in the hole sizes and spacing. I've heard good things about Treebone. Not long ago they moved to Cimarron, New Mexico, just a few miles from where I plan to make my new home -- when I sell my darn house.

Weak M 71 Browning hammer springs

Weak M 71 Browning hammer springs

M 71 mainspring.

M 71 mainspring.

Re: M 71 mainspring.

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