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Updating Brno firing pin springs!

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I was told that one of J&P Customs overseas customers told them the CZ firing pin spring kits for the 452's would work with the Brno no.1 therefore the 1's thru 5's, I knew they were similar but only owning no.1's I wasn't sure. I got two of the 452 springs and tore down my two no.1's and can cheerfully report they work great with the Brno's also.


The upper spring in the photo is the new J&P 452 spring, slighty longer and much more uniform in appearance, the lower spring has only been in this 49 stamped rifle 59 years or so so we can forgive it a kink or two.



In this photo the casing was fired in my 1949 stamped no.1 at the range last week, the indent from that firing is on the left side of the case, the upper indent is after replacing the firing pin spring. Hopefully from the photo you can tell there is a very considerable increase in the indent, this should mean better ignition and hopefully better accuracy. I hope to range test both rifles in the near future, but feel the newer spring is worthwhile from a reliability stand point if nothing else.

Gerald
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Discussion Starter · #4 ·
Sorry Hornet, I did not, I was in a bit of a rush trying to get several things I'd had to put off the last week or so done. I show a greater difference than that on the two springs I removed, 2.423 and 2.523, the replacements were longer than either of these.

Gerald
 

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Hi guys,
I also fitted the firing pin spring to my 1957 Model 2 and can say it gives you the feel good factor that may well be the match winning edge, not saying the firing pin spring will win you the match, I am just saying the feeling that everything is perfect with your gear may well be the edge. I also ordered and fitted the "CZ Rimfire Action Screw Set #1 " to my old Brno 1957 model 2 and they fitted with no hassle, and they do also fit to a model 5 (1958). I am quite sure they will fit all the model ones also. ok I am sure, I just checked them all, here we go;

A Model 1 (ZKM 451) 1950


The Early trainer stocked Model 2 (ZKM 452) 1956-57

here a close up to show screw profile and another pic to show the "Trainer Stock" shape incase you are not aware of the two stock types;



And this a Model 2 (ZKM 452) 1957 model with the more common "u" or schnabel type stock (here shown in sporting match garb, a moderator and strap on checkpiece;



And finally a Model 5 (ZKM 573) 1958


I had J&P ship them out to New Zealand a couple of weeks ago as soon as they went international, had no problems except my own stupidity in ordering
"KRIEGHOFF GUN GLIDE " which if I had bothered to read the spec would have told me "THIS ITEM IS NOT AVAILABLE FOR INTERNATIONAL SHIPPING", but they sorted that out easily and had the rest of the order away in good time, thanks guys.
If you have glass bedded your Brno and in doing so raised the action or lowered the trigger guard in the stock you may start to find there is not enough thread on the action screw, but in most instances I doubt it would be a problem and with the factory bedding you won't have any trouble. Cheers, Paul
 

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Discussion Starter · #6 ·
Now that's what we're looking for Paul, great news, had a feeling that once we started folks looking and "experimenting" we'd find these parts fit a lot of the Brno clan. Thanks for sharing with us :bthumb:, great photo's too!

Gerald
 

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Gerald : If you dry fire on a spent case you can clearly see that the firing pin strike marks are different. The mark made when dry firing will always appear deeper.
The mark made when firing a live shell will be rather "flat" bacause of the pressure builtup in the case pushing the brass back.
 

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Discussion Starter · #8 ·
Not trying to be argumentative but I just stepped out in the back yard and fired a PMC Moderator and its indentation is identical to what I observed with the dry fire, what you say may well be true with HV rounds but I seldom use them and none of those pictured were HV. I guess I'll stay with my contention that its giving a more positive indentation. Thanks.

Gerald
 

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Discussion Starter · #11 ·
Understood Nick, just reporting my observations, could the subsonic vs HV pressure make that much difference, I'm learning new things constantly and just trying to understand what I see.

Gerald
 

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Ahhhh an intersting point from my point of view at least is that it seems that the Brno Model 2's seem to have that light golden wood with the reddish and black streaks though it like the one in the photos mine is also like this as was another I saw for sale some years back. Oh mine is 1965 vintage.
 

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Sorry Gerard, going sideways

Hi Brithunter
I too had cause to mull over that streaking when I refinshed that stock, I wrote an article about that refinishing job that I may or may not get around to publishing or posting, but anyway here is a bit of my rambling on the subject;



Notice the razor edge of the wood, the butt plate will protect this and the epoxy finish will strengthen the wood itself, but right now it is very vulnerable, so treat it with extreme care. Now take a look at that end grain, my first thoughts were that the black mineral stain was very localized, perhaps just one year's growth ring! What happened? Volcanic eruption, fire, the wood probably came from Turkey, heck; it may even have soaked up a heap of mustard gas during WWI? Whatever caused it one would have to assume it was a very traumatic time for the tree. However upon closer scrutiny I came to realize that it is actually the transition between the duramen (heartwood) and alburnum (sapwood). The heartwood is basically dead and the sapwood draws all the minerals and water up into the crown of the tree. Once I realized this I could readily see it in this stock and a few other stocks as well, in the montage that follows I've drawn an oval on the first stock to represent the rough size and position of the heartwood on the log that the stock was taken from, I say log but probably by the size it would more likely be a limb, walnut has a very prominent pith running through the centre of every limb, this can be about 6mm in diameter and to be avoided, I imagine on a limb the mill would put the cut through the middle of the limb to negate the plinth and take one plank off each side of it, I believe that is what we are seeing on the two very similar stocks at the top of the montage;



I believe nearly all of New Zealand walnut I have handled is of the Juglans regia (English walnut) variety, where the transition from the dense heartwood, awash with chocolate browns blacks and purples, meets the plain pine-like sapwood, it's like night and day, as you can see in this blank;



End excerpt, Sorry to drag your thread off topic Gerard, Oh and Brithunter its more a general Brno thing rather than model 2's, the first three rifles in the montage are model ones and the last a 581 from memory, the Cheers, Paul
 

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Discussion Starter · #14 ·
Heck Paul never apologize for adding to the knowledge base, and I can look at good walnut and several other woods all day, I love beautiful wood! Thanks for posting.

Gerald
 

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Discussion Starter · #15 · (Edited)
Just a bit of a post script here, many of you may have noticed all of 35WCF's Brno's have hex head action screws, Pete at J&P had tipped me off to them also and I ordered up two sets for my Brno no.1's, they fit perfectly and make a welcome addition for me at least as I'm clumsy enough to worry about marring action screws and magazine plates with slot head screw. The modern springs and screws are really nice.
Before



After



Side view



They don't fit perfectly flush at the trigger guard but are very unobtrusive. A very nice addition to the known uses of their products. These are now listed under Brno action screws for models 1,2 and 5 and Brno striker springs for models 1,2,3,4 and 5.
Gerald
 
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