Malig8r Posted March 12, 2015 Report Share Posted March 12, 2015 On a slightly different note...does anyone know where or if I can buy a NP3 coated 308 BCG? I know lots of options for Nickel Boron but I'd like the NP3 option instead. Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted March 12, 2015 Report Share Posted March 12, 2015 I think NP3 is a form of salt bath nitriding or ferric nitrocarborization, no? If so, just look for a nitrided or Melonited BCG. Quote Link to comment Share on other sites More sharing options...
FaRKle! Posted March 12, 2015 Report Share Posted March 12, 2015 I think NP3 is a form of salt bath nitriding or ferric nitrocarborization, no? If so, just look for a nitrided or Melonited BCG.NP3 is nickel-teflon, different from nitriding. Quote Link to comment Share on other sites More sharing options...
Malig8r Posted March 12, 2015 Report Share Posted March 12, 2015 NP3 is nickel-teflon, different from nitriding. You are correct sir...not that I would expect anything less. So...options? Quote Link to comment Share on other sites More sharing options...
FaRKle! Posted March 12, 2015 Report Share Posted March 12, 2015 You are correct sir...not that I would expect anything less.So...options?Unfortunately I haven't seen any standalone ones. I know my PWS has an NP3 bolt, but you'd need one you could put gas rings on. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 12, 2015 Report Share Posted March 12, 2015 I have a POF NP3 Upper Receiver & its silver ,like , in color. Quote Link to comment Share on other sites More sharing options...
shepp Posted March 13, 2015 Report Share Posted March 13, 2015 Say your looking into off caliber bolts? Like say 7.62x39??? Quote Link to comment Share on other sites More sharing options...
Malig8r Posted March 14, 2015 Report Share Posted March 14, 2015 Received my Master BCG Spare Parts Kit in the mail today. Ordered it on the 12th and got it in the mailbox on the 14th! Very impressive! Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 15, 2015 Report Share Posted March 15, 2015 Photo's <thumbsup> Quote Link to comment Share on other sites More sharing options...
ironmonster Posted March 15, 2015 Report Share Posted March 15, 2015 I got mine in the mail today too... Here are some thoughts and pictures. There is the Wilson bolt, Aero bolt and Aims bolt side by side in that order Here is the Wilson and Aero extractor parts removed from the bolt. Here is the Wilson extractor installed on the Aero bolt. Seems Skookum A couple close ups to show quality of machine work and over all appearance Ok first off, The D. Wilson bolt is purdy, the finish is finer and over all looks to be a superior bit. I would guess the extractor on both the Aero and Aim's bolts are forged and the Wilson machined. Really the Wilson looks like a higher quality bit. So.... I put the new Wilson bolt in the Aero carrier and ran it in into the barrel extension. It wanted to stick, I had to pop it a few times in and out to get it to come out of the gun. It had some oil on it and it never locked up but it was not nice and smooth. I checked headspace, It would not close on the No Go, It did close on the go but just barely, I actually had to pop the back of the carrier pretty hard to get it into battery and then I had to tap on it with a brass punch to get it to unlock and come out. After that I tried just cycling it several times and the bolt wants to hang up. It never got stuck, but a time or two I thought it might. Worst one it took maybe a few minutes of gentile tapping with a brass punch before it came lose. I actually expect that that its just an exceptional fit, I think a few hundred rounds through the thing and it would be better than either of the others just based on the quality of the machine work. The only way shipping could have been faster is if they where teleported to my mailbox. All the spares look top notch. I ordered the master kit as well as a complete spare bolt and there is nothing even questionable, everything looks top tier super wazzu skookum Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 15, 2015 Report Share Posted March 15, 2015 (edited) Damn, I didn't check the mail today... Yep, it's in the box - I'll grab it in the morning. Edited March 15, 2015 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Red_SC Posted March 20, 2015 Report Share Posted March 20, 2015 I've been considering branching out into what I call off-caliber bolts lately as there's been a handful of people that have contacted me about them. Have you considered a BCG with a small firing pin? This platform is taking off in various 6mm and 6.5mm calibers, and a lot of us are buying small firing pin bolts to reduce primer piercing that's more common in those calibers. The few available like the JP are twice the price of a standard BCG. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 20, 2015 Report Share Posted March 20, 2015 Small firing Pin Bolts ? Whats the difference , except the obvious . Photo's of the differences ? Quote Link to comment Share on other sites More sharing options...
Red_SC Posted March 20, 2015 Report Share Posted March 20, 2015 (edited) Small firing Pin Bolts ? Whats the difference , except the obvious . Photo's of the differences ?The firing pin is smaller, around .062, to reduce pierced primers. This is a lot bigger problem on 6mm and 6.5mm calibers than .308. I know JP and Rubber City make a small firing pin BCG they call a High Pressure bolt, and LMT bolts and the newer DPMS G2 are supposed to have small pins by default. Here's a pic I found comparing JP's standard and HP bolts.http://williamjmeyer.com/SH/LW_AR308_Build_0008.jpg Edited March 20, 2015 by Red_SC Quote Link to comment Share on other sites More sharing options...
Red_SC Posted March 20, 2015 Report Share Posted March 20, 2015 Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 20, 2015 Report Share Posted March 20, 2015 And this stops the primer blow outs ? Quote Link to comment Share on other sites More sharing options...
Red_SC Posted March 21, 2015 Report Share Posted March 21, 2015 It reduces pierced primers or primer blanking, but it doesn't do anything to keep primers from coming out of the pockets. Quote Link to comment Share on other sites More sharing options...
unclemoak Posted March 22, 2015 Report Share Posted March 22, 2015 Interesting. I'd never heard of this before. Quote Link to comment Share on other sites More sharing options...
Malig8r Posted March 22, 2015 Report Share Posted March 22, 2015 The firing pin is smaller, around .062, to reduce pierced primers. This is a lot bigger problem on 6mm and 6.5mm calibers than .308. Ok, help me understand this...how can a smaller firing pin reduce pierced primers? My thought process would lead me to believe the opposite to be true since a larger firing pin would have a greater surface area and thereby distribute the pressure of the impact over that greater surface area. Whereas a smaller firing pin should have an increased incident of pierced primers since the impact force is more focused and not distributed. I just don't get it. Help me to understand please. Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted March 22, 2015 Report Share Posted March 22, 2015 "High-Pressure bolt" makes more sense...smaller firing pin hole for escaped gases from a ruptured primer to travel through. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 22, 2015 Report Share Posted March 22, 2015 High pressure is probably whats really going on . A smaller firing pin dia. may help , because it would contain the primer indentation more to the center of the Primers Anvil , but that still would not eliminate it completely , its still high chamber pressure that is probably the cause , no matter what the size of the Firing Pin. Primers coming out of the pocket of a good case is a high chamber pressure sign also. I would go a much different route to eliminate the problem . Quote Link to comment Share on other sites More sharing options...
Red_SC Posted March 23, 2015 Report Share Posted March 23, 2015 Ok, help me understand this...how can a smaller firing pin reduce pierced primers? My thought process would lead me to believe the opposite to be true since a larger firing pin would have a greater surface area and thereby distribute the pressure of the impact over that greater surface area. Whereas a smaller firing pin should have an increased incident of pierced primers since the impact force is more focused and not distributed. I just don't get it. Help me to understand please. Sure. The primer isn't being pierced by the firing pin, but by the case pressure. The hammer falls on the pin, which flies forward and impacts the primer, dents it, and stops. The primer ignites the powder and pressure builds. The majority of the case head is supported, but the firing pin hole is a spot under the thinnest part, the primer cup, that is supported only by the resting firing pin. Having a smaller firing pin hole makes the unsupported area smaller. I don't know why, but many 6mm or 6.5 loads that are safe and show no primer pocket loosening or case head expansion will have a primers flow back into the firing pin hole or pierce in AR's, but it doesn't seem to happen often to .308's. Accuracy International rifles also have this issue, 308's run perfectly and many people have no issue with smaller calibers, but a significant number of people have had factory ammo or handloaded starting loads that pierced primers. The answer there is to have the firing pin turned down and the bolt face bushed, but few smiths will do it to the hardened AI bolts. I know I'd be hesitant to do it. Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted March 23, 2015 Report Share Posted March 23, 2015 That makes a lot of sense Red. Just a guess but I'd reason out that the smaller cases are more prone to pressure variations, due to smaller case capacity. A powder fluctuation of 0.3 grains of powder in a .308 has less effect than 0.3 grains fluctuation on a 5.56/.223 sized case. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 23, 2015 Report Share Posted March 23, 2015 It happens to 308AR's also , its happened to me , when I hand load a cartridge to too high of chamber pressure. If the firing Pin hole in the Bolt face is too large , letting the Primer flow into the gap when cartridge is fired , weakening the primer cup . It would happen to a smaller Firing Pin also if the Hole for the firing Pin is too large also . I think it has nothing to do with FP size. Just so you know , when a Cartridge is set off buy striking the Primer , the Primer actually backs out of its pocket slightly from the ignition pressure & with the pressure expanding the case , the Primer is basically , re-seated into the case . This may also be a case of the wrong manufacturers primer for the pressure exerted on it . - Has anyone did a survey on primers used & what Manufacturer ? - Have they tried MilSpec Primers ? Quote Link to comment Share on other sites More sharing options...
Red_SC Posted March 24, 2015 Report Share Posted March 24, 2015 Changing primers helps, but doesn't always solve the problem. My theory on why it's more common on other calibers than it is in .308 is the powder used. The case capacity is very close, but a .260, 6.5 Creedmore, or 6.5x47 shooting 123-142gr bullets or a .243, 6 Creed, or 6x47 shooting 105-115's typically uses a slower powder like 4350 or RL22. I'm guessing the high pressure part of the pressure curve is fractionally longer with the slower powder, putting pressure on the unsupported primer over the firing pin hole for a little longer. Whatever the case, the phenomenon is fairly common in these calibers, and JP has sold a ton of their high pressure BCG's at close to $500 a pop to fix it. Quote Link to comment Share on other sites More sharing options...
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