LugerForum Discussion Forums - View Single Post - Borchardt-Luger Controversy

Doubs · 08-20-2002, 12:19 AM

[quote]Originally posted by Jerry Harris:
<strong> Doubs, When I first pondered the ear, thoughts very similar to yours crossed my mind. It's true that the effort expended by the ear in compressing the striker spring will later feed back as a small additional breech-closing force. But it's so wimpy (won't even overcome friction) that we probably shouldn't count it as an engineering reason for adding the feature.</strong><hr></blockquote>

Jerry, I've pondered Unspellable's points but cannot completely agree that the PRIMARY purpose of the ear is to retract the firing pin to aid ejection and feeding. There are simply too many successful designs that, in the case of submachineguns, use a fixed firing pin or pistols with a firing pin that is pushed back by the new cartridge being chambered. e.g., the VZ-52 pistol.

My point was that the force necessary to compress the firing pin spring from it's rest position to the cocked position can not be reliably done by sear/firing pin engagement in the final movement of the toggle train as it seats the new cartridge and locks. Without the compression being provided on the recoil cycle when plenty of force is available, a reliable cocking and closure would not be possible.

I'm not downplaying the importance of safety or the benefits of the firing pin being retracted as an aid to ejection and feeding. It's just my opinion that they are secondary considerations to reliable cocking of the firing pin and closing of the action. The pre-compression of the spring also lessens the impact of the sear against the firing pin projection.... both somewhat delicate surfaces. Military primer cups are normally made harder than their civilian counterparts so a slam fire isn't likely. If that were not so, fixed firing pins combined with open bolt designs would not be possible.

As for the firing pin spring helping to soften the impact of the toggle train in it's rearward most movement, the firing pin keeper is slotted so that the toggle link to the recoil spring fits into it. The keeper does contact the link but the cushioning affect protects the link from damage due to being pounded repeatedly by an ungiving piece of steel. Any lessening of the recoil forces to the remainder of the train would seem incidental and not the primary reason for the free movement of the keeper. (Datig's book calls the "keeper" or firing pin spring guide the "breechblock end piece" which is too long to use here. Hence "firing pin keeper" or simply "keeper".)

Anyway, that's my opinion and I'm open to being convinced otherwise if the evidence is strong enough.

08-20-2002, 12:19 AM	#64
Doubs User Join Date: Jun 2002 Location: Byron, Georgia Posts: 1,736 Thanks: 819 Thanked 1,769 Times in 586 Posts	[quote]Originally posted by Jerry Harris: <strong> Doubs, When I first pondered the ear, thoughts very similar to yours crossed my mind. It's true that the effort expended by the ear in compressing the striker spring will later feed back as a small additional breech-closing force. But it's so wimpy (won't even overcome friction) that we probably shouldn't count it as an engineering reason for adding the feature.</strong><hr></blockquote> Jerry, I've pondered Unspellable's points but cannot completely agree that the PRIMARY purpose of the ear is to retract the firing pin to aid ejection and feeding. There are simply too many successful designs that, in the case of submachineguns, use a fixed firing pin or pistols with a firing pin that is pushed back by the new cartridge being chambered. e.g., the VZ-52 pistol. My point was that the force necessary to compress the firing pin spring from it's rest position to the cocked position can not be reliably done by sear/firing pin engagement in the final movement of the toggle train as it seats the new cartridge and locks. Without the compression being provided on the recoil cycle when plenty of force is available, a reliable cocking and closure would not be possible. I'm not downplaying the importance of safety or the benefits of the firing pin being retracted as an aid to ejection and feeding. It's just my opinion that they are secondary considerations to reliable cocking of the firing pin and closing of the action. The pre-compression of the spring also lessens the impact of the sear against the firing pin projection.... both somewhat delicate surfaces. Military primer cups are normally made harder than their civilian counterparts so a slam fire isn't likely. If that were not so, fixed firing pins combined with open bolt designs would not be possible. As for the firing pin spring helping to soften the impact of the toggle train in it's rearward most movement, the firing pin keeper is slotted so that the toggle link to the recoil spring fits into it. The keeper does contact the link but the cushioning affect protects the link from damage due to being pounded repeatedly by an ungiving piece of steel. Any lessening of the recoil forces to the remainder of the train would seem incidental and not the primary reason for the free movement of the keeper. (Datig's book calls the "keeper" or firing pin spring guide the "breechblock end piece" which is too long to use here. Hence "firing pin keeper" or simply "keeper".) Anyway, that's my opinion and I'm open to being convinced otherwise if the evidence is strong enough.