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Benevolence

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About Benevolence

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    Finally read the FAQs
  • Birthday June 29

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  • Location
    Denver, CO
  • Real Name
    Byron McArthur

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  1. Not sure what design route you're going for, but I would start with a 80% or junky lower, drill some holes for retaining pins across the magwell to fit your magwell features/prototypes in. Design the prototypes in solidworks and find someone that can 3d print them out of polymer and ship them to you. Shouldn't be expensive and you avoid gunsmiths/FFLs.
  2. If I understand correctly, you’re saying the gas behaves incompressible until it begins expanding in the carrier, and restricting at the gas port only increases the velocity, decreases the delivered mass and doesn’t affect the pressure of the gas. And that the benefits of the gas length are two fold; decreased port (and delivered) gas pressure and velocity into carrier. I suppose the Fat Boy or (perhaps more gimmicky) pig tail gas tubes could be an option. Oh, and I don’t really see how measurements of pressure at the ports and carriers are irrelevant or table talk; I
  3. Thanks; I’ve read a fair amount and your posts seem to have some good content so I was hoping to get your thoughts. Also how easy it is to be flat out wrong with over analyzing things without actually trying it and overlooking things that are important. Just trying to understand the recoil from a fundamental perspective. I’ve got a 11.5” carbine (Spikes) JP SCS with white spring and thinking about replacing the steel weights with a Teflon spacer. That, and milling lightening cuts in a F/A carrier and putting in a POF cam pin. Hoping to use the AGB in conjunction with it to get the
  4. Huh, that’s interesting. This mil report (BRLR 1475) seems to show the bolt carrier pressures only hitting about 2.5ksi, which seems like there’s expansion and restriction of that metered gas to a lower pressure than the chamber pressure. I’d think further restriction by a restrictive adjustable gas block would lower that carrier pressure more? From another article showing gas port size (restriction) effects on carrier chamber pressure: Maybe @TonytheTiger has some input on this?
  5. I’m going to nerd out here a bit in order to describe my understanding of the gas operation and but I was hoping to have a discussion about the effects of barrel length on recoil and the methods of reducing recoil. The general consensus as I understand is that a 18” rifle gas length AR is the lowest recoil barrel-gas system combination. It has a 12” port distance, with 6” of dwell length and 0.13ms of dwell time. Pressures are 19.6ksi at the port and 14ksi at the muzzle. I would consider this the ‘working pressure’ range that is used to operate the carrier during the pressure stages when it i
  6. Try forcefully inserting a mag with the slide off, ejector on, but unpinned. Does it lift up the ejector? If so, that’s your problem and where you’ve got to remove material. Also make sure to try it with a fully loaded mag to see if the brass presses it. Just my thoughts, take it for what it’s worth.
  7. I had that issue and it was the magazine over insertion bending the ejector up and out into the slide. The dawson precision mag release seems to have fixed it after I replaced the ejector, but I took some material off the bottom to prevent it from happening again if I really slam a magazine home.
  8. Okay, thanks for the information, I appreciate it. I am returning the cylinder reamer and decided to rent a 460 Rowland reamer and do it right especially with how high pressure of a cartridge this is.
  9. I purchased a Clymer .45 ACP reamer with the intent to ream a barrel out to fit a 460 Rowland (I have the compensator and stiffer recoil spring, and this is in a fnx45T). Unfortunately, in my naivety I got a cylinder and not a barrel reamer so the solid pilot is larger and doesn’t fit (.455 vs .445 I believe). It also appears that the cylinder reamers have a constant diameter throat whereas the barrel reamers have a taper ‘lead-in’? I was thinking of turning down the solid pilot to fit in the rifling and use to ream the extra 0.063” required for the 460Rowland. My question was if
  10. I think it was several things, and I took some material off of the front of the sear feet and put a tiny bend in the back of the trigger bow. This should allow the disco to raise when the sear is engaging the hammer. Whether it truly was the hammer/sear hole locations I’m not sure but it definitely wasn’t the best. Appear to have it working now
  11. True, I was kind of worrying about that as well. I’ve got a 3/16” ball nose carbide endmill I could bore out the sear/disco hole with, and turn some hard steel for a press in sleeve (have access to LN2 and a torch). Hopefully the endmill is rigid enough to keep center.
  12. Great, thanks. I hope the oversized pins are large enough and I can true up the sear/hammer holes in the frame. I feel like I did good on fitting the slide and barrel to the frame so this is a bit of a shame.
  13. Well, just to update that I feel like an idiot. Looks like the sear to hammer hole are a few thou out of alignment (drill bit wandering during drilling, not(?) during the first part. Should have undersized and reamed) and the sear legs are partially catching on the disco when it’s trying to reset. That, combined with the sear-hammer engagement is likely not aligned great. Hopefully redeemable by fitting the sear to accommodate. Not desirable though and frustrating. Should have just done a complete frame like I did on my first.
  14. Hi all, I hope to not make this too lengthy. I’m building my second 2011 and I did a 80% lower (mill rails, drill hammer/sear holes using center drill then drill bits on a mill with DRO so the dimensions should be accurate but I’m now maybe suspect). I am having some weird issues that are hard to replicate. Upon occasional dry firing, I am unable to ‘fire’ the gun and the hammer stays cocked. The trigger moves as it should and the disconnector moves forward and back. Upon inspection, the disconnector is staying down and the sear legs are too far towards the muzzle to allow the disconnector to
  15. I had this same issue and it was quite frustrating. I marked the points of contact in the thread below, but essentially you end up with a pivot point at the top of the barrel, about half way back, with the other two points of contact being the bottom of the barrel with the slide, and the barrel locking lugs trying to engage the slide locking lugs. You've got to either raise the pivot point (remove material from the top of the barrel), or lower the other limiting point (bottom of barrel with slide). I ended up electing to remove material from the slide (where the front & bottom of the barre
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