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Double Rifles, Single Shots & Combinations >> Building Double Rifles & Gunsmithing

oupa
.300 member


Reged: 01/03/06
Posts: 127
Loc: Maryland,USA
Re: Odd problem, suggestions, guesses, etc. ???
      03/12/10 09:08 AM

Well I've been back at the 30-30 hammer gun recently and the final result is that I've decided to scrap the project, at least on this action. An explaination is in order if only to aid those budding builders out there...

The original subject of this thread - loose barrels I attributed to sloppy threading - may or may not be correct in light of recent discoveries. The action in question while old is quite heavy. Together with the relatively mild 30-30Win. cartridge at a standard 2100fps loading I assumed would be perfectly safe. Enter the old caution about "assume" (ass of u and me).

After carefully refitting the barrels and rechambering I went back to the range. Testing went fine and "proof loads" did not indicate any problems.... Now for the regulation!

The first attempt proved the barrels pleasingly close, within three inches laterally and perfectly even horizontally! However it was crossfiring... The second attempt showed my estimes were woefully off with considerable deviation between barrels. Back to the shop and aided by a laser bore sighter shining on the shop wall with the barrels in the vise I carefully estimated the difference between where it was and where I moved it to, again with essentally guessing where that movement might end up in reality at fifty yards but at least confident on joint elevation.

All this testing (along with just having fun) amounted to something around thirty rounds of regular ammo and four (two each side) "proof loads." During the last range session I began to notice some troubling signs. Namely the action was getting "sticky" to open. Not stuck but unusually tight after being fired. This began gradually with just the ocasional ocurance and progressed to every time. Between shots and unloaded it seemed fine though and careful examination and even measurements did not indicate any change in the dimentions of the action. All along I have had some deformed primers but due to the nature of the rifle I hadn't put much concern in it. I attributed the stickyness to the primers. During the second range session I had also begun to encounter an ocasional failure to fire on the first hammer drop but always firing if I re-cocked and tried again... Hmmmm. I attributed THAT to the previous assumption that the hammer faces needed some re-working... Hmmmm.
More examination and measuring failed to show ANY signs of elongation of the action and head space was still good... Hmmmm. This was really vexing me and I repeatedly ran all of it over and over in my mind. In my zeal for success on this particular action I decided I was making excuses for individual issues that are in fact ALL attributable (and obvious signs of) ONE issue. Plasticity! In short the action is streching momentarily under stress and returning to original dimension after pressure is relieved, however some things such as the deformed primers and sticky lug and crossbolt remain after the fact. The too short firing pin reach could be attributed to the continued (miniscule) elongation that may remain during periods of extended firing... It seems to make sense anyway. The original gun was quite old which would suggest the possibility of questionable steel that could lead to this situation even though the action appears more than heavy enough. Another reason to only use a donor gun of documentable "proof" and good condition even for relatively mild chamberings.

Continuing in this condition will eventually lead to failure - coming off-face, excessive headspace, cracking or even breaking of the action as continued flexing work-hardens it. One easy solution would be reduced loads. I WILL NOT however build any firearm for a factory cartridge not capable of factory ammunition. You see one day it will be owned by someone else who may not know or observe my built-in limitations... I'd hate to be sitting in heaven one day and meet someone arriving as a result of something I set in motion. No, this project is canciled!!! I may try fitting a pair of .22CF barrels I have in the shop for a hornet... that should be safe. I also have several donor actions / guns around that I may re-fit the 30-30 barrels to if deemed to be long enough. I will eventually build a 30-30 though. It makes a perfect deer rifle for the woods where short ranges and ease of swinging it are more important than when sitting in a box stand in a bean field and the 30-30 has long ago proven its reputation on whitetails under such conditions... plus its just a neat little round.

The moral to this story is to keep an open mind. While it'd be easy to remain quiet on my arguably predictable failures, I hope my posting them here will save others making the same mistakes. This is a " whole nother ballgame " from screwing together a modern bolt action rifle! Something I've done often and some say well. Not content with the status quo however, I will continue until succeeding at this higher art!

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Entire topic
Subject Posted by Posted on
* Odd problem, suggestions, guesses, etc. ??? oupa 31/10/10 10:56 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? oupa   25/11/10 03:39 PM
. * * Re: Odd problem, suggestions, guesses, etc. ??? CHAPUISARMES   25/11/10 04:30 PM
. * * Re: Odd problem, suggestions, guesses, etc. ??? Ron_Vella   26/11/10 12:11 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? oupa   26/11/10 09:49 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? oupa   03/12/10 09:08 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? 4seventy   04/12/10 11:56 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? oupa   05/12/10 11:08 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? AkMike   04/12/10 12:30 PM
. * * Re: Odd problem, suggestions, guesses, etc. ??? doubleriflejack   04/12/10 08:50 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? 4seventy   04/12/10 11:51 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? doubleriflejack   10/12/10 07:49 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? 4seventy   10/12/10 10:32 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? Huvius   01/11/10 02:52 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? Oldbrit   01/11/10 03:54 AM
. * * Re: Odd problem, suggestions, guesses, etc. ??? oupa   01/11/10 02:29 PM

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