blowback vs. locked breach: Berdan vs. Boxer
I've seen these terms used in many different contexts. Can anyone define these four terms and explain the difference between these them? What are the pro's and con's of each. Thanks!
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Blowback: An action common to small caliber semi-auto pistols and submachine guns. The bolt or slide is not locked in the forward position; it is merely held forward by pressure from the recoil spring. When the gun is fired the bolt or slide recoils against the spring, is slowed to a stop and then forced forward by the spring back into battery. usually the bolt or slide is disproportionately heavy compared to guns that use delayed opening mechanisms.Locked Breech: The bolt or slide or barrel is locked in the forward position at the time of firing by lug(s) or shoulders. Rising pressures or recoil or gas or a combination of these factors cause the bolt/slide/barrel to unlock and move rearward.Boxer vs. Berdan primers: Oddly, Boxer was a European (Swiss) and Berdan was an American. The Boxer primer is used in America and the Berdan in Europe. The essential differences are that the Boxer primer has an anvil built into the primer cup and when fired discharges into the powder through one flash hole centrally located in the primer pocket. The Berdan primer cup contains only the priming compound, the anvil is built into the bottom of the primer pocket (is part of the cartridge case) and when fired discharges through two small flash holes off-set from the center. For this reason the Boxer primed case is easily reloaded as a punch can be inserted into the case mouth and the old primer knocked out. The Berdan is much more difficult to reload as the holes are not lined up with the case mouth. Although there are a couple of methods of removing Berdan primers most reloaders only use Boxer primed brass due to the hassle of removing fired Berdan primers and obtaining new ones. 0 -
Thanks for your clear, thorough explainations! What are pro's and con's of locked breach vs. blowback? Also, how does the locked breach recycle forward after firing? A recoil spring? Thanks! 0 -
Most decent pistols of 9mm or bigger caliber use locked breech actions. Blowback is reserved for the smaller, lower pressure rounds. If the caliber is equal, say the .380 ACP, there are some noticeable differences. There are locked breech and blowback pistols in this caliber. If you take a blowback gun, say a Walther PPK, and shoot it next to a locked breech gun, say a Colt Gov't .380, you may notice that the blowback gun has more felt recoil. I think the locking breech delaying the opening of the action spreads the recoil impulse out over a longer moment.
Certified SIG pistol armorer/FFL Dealer/Full time Peace Officer, Egotistical Rogue, Evil, Dangerous Racist Moderator of the General Discussion Board on Gunbroker. Email davidnunn@texoma.net Jesus is Lord!0
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