This gun was almost certainly having the block openĭuring firing, at least a small amount, or was capable of such an occurrence if some certain heavy loads were shot more frequently. This type of situation is like a brake dragging metal to metal: when the first bit occurs, you might not be sure of what you heard due to the faintness of the noise. I'm sorry if my posting seemed to lay blame for not noticing a problem that had been progressing. A scar is a scar, and we would only be debating the level of damage.įace it- your parts have suffered damage that needs repair to be reliable and safe. If it was a fact that your spring needed to be periodically replaced to prevent a blow-open possibility, just because it is a (fill in the blank), you would have needed to change it before the gun lock-up had shown any apparent motion, or else you would have already waited too long, just like the grinding brake sound shows that you have already cut into the brake disc. Reducing the load that you shoot may stop your gun from blowing open, for now. Replacing your spring may keep your gun from blowing open, for now. Makes sense to me, until you hit a guardrail, that is. If your gun is blowing open, replace a spring. If your brakes are grinding, turn up the stereo. A stiffer spring might be able to keep a small amount of contact during firing of light loads, but the slide out and back will still occur, not heal itself, but will deteriorate to a point of blow-open with possibly worse consequences, since the poor contact was carelessly allowed to continue. Here is one example of a blowing open wear pattern. You have an edge that has started to roll over from pressure exertion across a limited contact surface (since contact amount reduces as the sliding occurs), and the barrel locking lug and bolt surface are both being affected, with some reduction of needed contact surface on both parts. The bad wear condition is already set in motion and can't be reversed any more than a tooth cavity will go away from harder brushing. If your mechanism has exhibited any slippage during firing, the wear condition that has started will not be alleviated by replacing a spring. A wedge should never slide out, just like a simple doorstop works, and if it does slide out, then the angle of engagements, surface finish, level of contact, and more are all considered suspect. The friction between the parts prevents any camming motion when under firing pressure, since a proper fit is at such a mechanical disadvantage. If your spring was the only thing containing the motion, and needed to be like new condition to prevent blow-open, then your mechanism was defectively fitted or has worn into a slip-slide condition.Ī new and properly fit locking mechanism needs no spring to prevent blowing open if the parts are initially set into proper position. The mechanism has no provision to safely allow any motion AT ALL during the high pressure phase of firing. A locking block moving during firing should never be considered as normal.