Alex C. Posted January 28, 2016 Report Share Posted January 28, 2016 Does anybody have a textbook definition of positive extraction? Viewers constantly ask me what the fuck I'm talking about when I mention it and I would like to make a video explaining what it is. It is also discouraging that I was at the Dallas Safari Club show and a Blaser rep stared blankly at me and asked what I meant when I commented on it. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted January 28, 2016 Report Share Posted January 28, 2016 "Positive" extraction? Do you mean primary extraction? Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted January 28, 2016 Report Share Posted January 28, 2016 Hey... I recognize that range: Quote Link to comment Share on other sites More sharing options...
Alex C. Posted January 28, 2016 Report Share Posted January 28, 2016 Primary, yes. Quote Link to comment Share on other sites More sharing options...
Donward Posted January 28, 2016 Report Share Posted January 28, 2016 Can you suppress a gun with positive extraction? Quote Link to comment Share on other sites More sharing options...
Collimatrix Posted January 28, 2016 Report Share Posted January 28, 2016 Primary extraction is the recovery of petroleum by purely mechanical means such as a pump jack. This differs from secondary oil extraction in that... Oh wait, you were talking about guns. Primary extraction is where the initial stage of the bolt's extraction of the spent case is done with a mechanical advantage. Some people will say that the very act of rotating the bolt during unlocking serves the same purprose; to "unstick" the case from the chamber walls by spinning it around. They are obviously full of shit, the extractor will just slide around in the groove if the case is meaningfully stuck as anyone with eyes can see. In a number of bolt action rifles primary extraction is accomplished by having a diagonal portion of the bolt's path after it unlocks. This acts as a cam to lever the bolt rearwards as the shooter lifts the bolt handle. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted January 29, 2016 Report Share Posted January 29, 2016 Primary extraction is the recovery of petroleum by purely mechanical means such as a pump jack. This differs from secondary oil extraction in that... Oh wait, you were talking about guns. Primary extraction is where the initial stage of the bolt's extraction of the spent case is done with a mechanical advantage. Some people will say that the very act of rotating the bolt during unlocking serves the same purprose; to "unstick" the case from the chamber walls by spinning it around. They are obviously full of shit, the extractor will just slide around in the groove if the case is meaningfully stuck as anyone with eyes can see. In a number of bolt action rifles primary extraction is accomplished by having a diagonal portion of the bolt's path after it unlocks. This acts as a cam to lever the bolt rearwards as the shooter lifts the bolt handle. The AK and the Garand both do the same thing, but I don't think they achieve PE, either. Mausers definitely do, as their extractors are tensioned in such a way that they are forced inward against the case extractor groove and rim, pulling the case tight against the bolt face. When the bolt rotates and cams slightly, the extractor is actually gripping it in such a way that it can break the case free of the chamber if it's stuck. An M1 or AK have that helical camming action, but their extractors aren't nearly as aggressive in gripping the case. Quote Link to comment Share on other sites More sharing options...
Collimatrix Posted January 29, 2016 Report Share Posted January 29, 2016 That's a good point. For PE to work you almost have to use a Mauser-style extractor. The distance that the bolt pops back during PE is so small that the distance will be taken up by the extractor rather than popping the case loose. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted January 29, 2016 Report Share Posted January 29, 2016 That's a good point. For PE to work you almost have to use a Mauser-style extractor. The distance that the bolt pops back during PE is so small that the distance will be taken up by the extractor rather than popping the case loose. Also, your extractor needs to have a death grip on the case to actually break it free. Quote Link to comment Share on other sites More sharing options...
Meplat Posted January 29, 2016 Report Share Posted January 29, 2016 That's a good point. For PE to work you almost have to use a Mauser-style extractor. The distance that the bolt pops back during PE is so small that the distance will be taken up by the extractor rather than popping the case loose. I knew a 'smith in the Phoenix area who was messing with what he called a "true collet" extractor. In that, except for a cut for an ejector plunger, when the round was chambered the "extractor" closed around the majority of the case extraction groove similar to the collet of a Hardinge lathe. I don't know if he ever worked the bugs out, it seemed to usually work, but when it would grab onto a slightly oversize case, you had to pull the bolt to separate the two. Collimatrix 1 Quote Link to comment Share on other sites More sharing options...
Collimatrix Posted January 29, 2016 Report Share Posted January 29, 2016 I knew a 'smith in the Phoenix area who was messing with what he called a "true collet" extractor. In that, except for a cut for an ejector plunger, when the round was chambered the "extractor" closed around the majority of the case extraction groove similar to the collet of a Hardinge lathe. I don't know if he ever worked the bugs out, it seemed to usually work, but when it would grab onto a slightly oversize case, you had to pull the bolt to separate the two. Damn. If that doesn't get the job done, then your case spec needs scrutinized. Quote Link to comment Share on other sites More sharing options...
Meplat Posted January 29, 2016 Report Share Posted January 29, 2016 Damn. If that doesn't get the job done, then your case spec needs scrutinized. It was an amazing bit of millwork, all I remember was the "bolt" was a series of telescopic sections, whereby on chambering the round was momentairly held as the collet-extractor closed on the groove, and during extraction there was a point where the collet released as the ejector plunger poked the case out. Oddly, he chambered the rifle for 7,62 NATO, I guess to really give it a workout regarding case variation and potentially cash in on the "tacticool snipar" market. ETA- His name was "Lars Larssen" (or something very similar), and last I knew he was running a shop in Cave Creek. He was pretty much who I sent people to who had the misfortune to own H&K P7's or those odd "SL" series sporting self loaders. (I loathed working on H&K products at the time, and still mostly avoid them. Lars did not have sausage fingers and blacksmith hands, so he had no issues with the silly things) Quote Link to comment Share on other sites More sharing options...
Alex C. Posted January 29, 2016 Report Share Posted January 29, 2016 Primary extraction is where the initial stage of the bolt's extraction of the spent case is done with a mechanical advantage. Some people will say that the very act of rotating the bolt during unlocking serves the same purprose; to "unstick" the case from the chamber walls by spinning it around. They are obviously full of shit, the extractor will just slide around in the groove if the case is meaningfully stuck as anyone with eyes can see. In a number of bolt action rifles primary extraction is accomplished by having a diagonal portion of the bolt's path after it unlocks. This acts as a cam to lever the bolt rearwards as the shooter lifts the bolt handle. Would the Mauser's bolt handle acting against the diagonal cut of the receiver bridge be its source of primary extraction? That has always been my understanding. Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted January 29, 2016 Report Share Posted January 29, 2016 Would the Mauser's bolt handle acting against the diagonal cut of the receiver bridge be its source of primary extraction? That has always been my understanding. That is what forces the bolt to work against the cams, but it's the extractor doing most of the work. Quote Link to comment Share on other sites More sharing options...
Alex C. Posted January 29, 2016 Report Share Posted January 29, 2016 Sure. I suppose it would be good to show the difference between a Mauser and a Carcano or something on camera to display how the bolt handle's interaction with the bridge is hugely beneficial to the system. Quote Link to comment Share on other sites More sharing options...
Collimatrix Posted January 29, 2016 Report Share Posted January 29, 2016 It's theoretically possible that the fulcrum is something other than the bolt handle stem; a bearing surface on a lug or something. I would carefully check the action before categorically stating it doesn't have PE. Quote Link to comment Share on other sites More sharing options...
Alex C. Posted January 29, 2016 Report Share Posted January 29, 2016 That's an issue I'm running into. There are great internet debates as to what rifles have primary extraction and which rifles do not. A la the AK47. Quote Link to comment Share on other sites More sharing options...
Donward Posted January 29, 2016 Report Share Posted January 29, 2016 That's an issue I'm running into. There are great internet debates as to what rifles have primary extraction and which rifles do not. A la the AK47. That sounds like a terrible internet debate. Quote Link to comment Share on other sites More sharing options...
LoooSeR Posted January 29, 2016 Report Share Posted January 29, 2016 Is this thing a turkish Uzkon BR99? Glory to Allakh! Glory to Takebeer! Quote Link to comment Share on other sites More sharing options...
Sturgeon Posted January 30, 2016 Report Share Posted January 30, 2016 The original drawing for the ".30 SL", which became the .30 cal. M1 Carbine: Quote Link to comment Share on other sites More sharing options...
LoooSeR Posted January 30, 2016 Report Share Posted January 30, 2016 Tied 1 Quote Link to comment Share on other sites More sharing options...
LoooSeR Posted January 30, 2016 Report Share Posted January 30, 2016 Alfa/Alpha team armory. Collimatrix 1 Quote Link to comment Share on other sites More sharing options...
LoooSeR Posted January 30, 2016 Report Share Posted January 30, 2016 Ak-103s in use, including with drum mags Collimatrix 1 Quote Link to comment Share on other sites More sharing options...
Tied Posted January 30, 2016 Report Share Posted January 30, 2016 Alfa/Alpha team armory. Looks like somethimg out of a movie Quote Link to comment Share on other sites More sharing options...
LoooSeR Posted January 30, 2016 Report Share Posted January 30, 2016 Bashar al-Assad having fun with an RBG-6/Milkor MGL Multiple Grenade Launcher. Tied 1 Quote Link to comment Share on other sites More sharing options...
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