Cocker anti-chop from PBN

russc · 01-29-2007, 12:06 PM

http://www.pbnation.com/showthread.php?t=1986486

He's put a spring in the ram, and plugged the return port on the 3way. Pretty cool!

kidneythief · 01-29-2007, 12:09 PM

I wonder if the ram closes fast enough...and if that has any effect on timing.

-Jake

russc · 01-29-2007, 12:13 PM

I figure that you'd probably want a decently stiff spring in there still. I see it as a sort of Sniper II return spring. You pump on the rear stroke, release on the forward.

kidneythief · 01-29-2007, 12:38 PM

Yeah but would still eed to be snappy. That looks like a pen spring...I just wonder if that spring would be able to push that kinda mass when you atart laying into the trigger. It is a good idea.

-Jake

HP_Lovecraft · 01-29-2007, 12:45 PM

The Montneel uses something like a pen-spring, but in reverse.

With the Montneel, the hammer cycle is 1/40th of a second, while the bolt cycle is 1/20th of a second. So, clearly in that example the spring slows down the bolt by 50%

However, while it might slow down the cocker, I would assume it is also less likely to chop... Hard to tell if that is a good thing.

nick

netsurferdude2 · 01-29-2007, 01:36 PM

WHat they should just do is buy a single acting spring-returned cylinder(Ram) instead of a double acting.

wolf13 · 01-29-2007, 01:50 PM

this is the same concept rebline used on some of their nelson semi auto conversions

Surestick · 01-29-2007, 02:15 PM

Looks bigger than a pen spring. I'd guess it's a cut down mainspring from a A5 or similar.

Slowcode · 01-29-2007, 04:39 PM

Wouldnt that cause problems with the max travel of the ram? Once fully compressed the spring still takes up space? Other then being different I dont get it.

Surestick · 01-29-2007, 05:00 PM

Quote:

Wouldnt that cause problems with the max travel of the ram? Once fully compressed the spring still takes up space? Other then being different I dont get it.

The ram never travels to the stop, it's stopped by the cocking rod's max travel.
As a 'cocker operates normally the ram has the same amount of force in both directions. The force needed to open the bolt is greater than the force needed to close the bolt because of the added resistance of the mainspring. Due to this the bolt generally has enough force to chop a ball when it closes the bolt. The idea here is to reduce the force that is closing the bolt to prevent chops.

01-29-2007, 12:06 PM	#1 (permalink)
russc MCB Member Join Date: Apr 2006 Location: Vancouver, BC Posts: 4,264	Cocker anti-chop from PBN http://www.pbnation.com/showthread.php?t=1986486 He's put a spring in the ram, and plugged the return port on the 3way. Pretty cool! __________________ YouTube Channel / Raincouver! / Gallery / Feedback / Blackleaf Outfitters -Russ

01-29-2007, 12:09 PM	#2 (permalink)
kidneythief Lord humungus the Mod Join Date: Mar 2006 Location: Home Finally!!! Posts: 2,447	I wonder if the ram closes fast enough...and if that has any effect on timing. -Jake __________________ "I wish simply to be a decent person, yet I will always fear the retards" -Brian Hindt(geech) "Every man knows he is, basically, a complete sissy compared to Johnny Cash." - Bono LPPC member #24 MCB Moderator Machinist for hire Kidney Machine

01-29-2007, 12:13 PM	#3 (permalink)
russc MCB Member Join Date: Apr 2006 Location: Vancouver, BC Posts: 4,264	I figure that you'd probably want a decently stiff spring in there still. I see it as a sort of Sniper II return spring. You pump on the rear stroke, release on the forward. __________________ YouTube Channel / Raincouver! / Gallery / Feedback / Blackleaf Outfitters -Russ

01-29-2007, 12:38 PM	#4 (permalink)
kidneythief Lord humungus the Mod Join Date: Mar 2006 Location: Home Finally!!! Posts: 2,447	Yeah but would still eed to be snappy. That looks like a pen spring...I just wonder if that spring would be able to push that kinda mass when you atart laying into the trigger. It is a good idea. -Jake __________________ "I wish simply to be a decent person, yet I will always fear the retards" -Brian Hindt(geech) "Every man knows he is, basically, a complete sissy compared to Johnny Cash." - Bono LPPC member #24 MCB Moderator Machinist for hire Kidney Machine

01-29-2007, 01:50 PM	#7 (permalink)
wolf13 MCB Member Join Date: Apr 2006 Posts: 870	this is the same concept rebline used on some of their nelson semi auto conversions __________________ looking for interesting cockers. especially AKA Black Widow, Slide trigger bonebrake, predators and other nice customs as well as perhaps an eclipse sovereign. CustomCockers.com Forum for Sniper 1's to MQ and anything autococking welcome. Pics of some of My Collection of 50+ rare and oddball cockers and other oddities

01-29-2007, 12:45 PM	#5 (permalink)
HP_Lovecraft MCB Member Join Date: Aug 2006 Location: Southern Maine Posts: 2,965	The Montneel uses something like a pen-spring, but in reverse. With the Montneel, the hammer cycle is 1/40th of a second, while the bolt cycle is 1/20th of a second. So, clearly in that example the spring slows down the bolt by 50% However, while it might slow down the cocker, I would assume it is also less likely to chop... Hard to tell if that is a good thing. nick

01-29-2007, 02:15 PM	#8 (permalink)
Surestick Seasoned Member Join Date: Nov 2006 Location: Montreal, Quebec, Canada Posts: 527	Looks bigger than a pen spring. I'd guess it's a cut down mainspring from a A5 or similar.

01-29-2007, 04:39 PM	#9 (permalink)
Slowcode MCB Member Join Date: Apr 2006 Location: MD Posts: 255	Wouldnt that cause problems with the max travel of the ram? Once fully compressed the spring still takes up space? Other then being different I dont get it.

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