GT8888 Posted November 23, 2020 Report Share Posted November 23, 2020 Are there typically issues with large-frame uppers that have no feed ramps when used with a barrel extension that has M4 feed ramps? Or would the magazine lip/wings just guide the round to the barrel extension ramps? thank you Quote Link to comment Share on other sites More sharing options...
Armed Eye Doc Posted November 23, 2020 Report Share Posted November 23, 2020 I am sure others will come along with their knowledge soon. However, I don't think there should be an upper without feed ramps. Got any pictures of one, or a link to to an example about which you are inquiring? Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted November 23, 2020 Report Share Posted November 23, 2020 1 hour ago, Armed Eye Doc said: I am sure others will come along with their knowledge soon. However, I don't think there should be an upper without feed ramps. Got any pictures of one, or a link to to an example about which you are inquiring? Pistol caliber (9mm) don't have feed ramps on some guns. Almost ALL rifle rounds require feed ramps to assist in loading of the round into the chamber. Please take a picture of the inside of the upper. Are you talking about the barrel extension NOT having feed ramps??? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted November 23, 2020 Report Share Posted November 23, 2020 Compare to this - tell what you have. Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted November 23, 2020 Report Share Posted November 23, 2020 10 minutes ago, 98Z5V said: Compare to this - tell what you have. Those pics look familiar ✓ Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 23, 2020 Author Report Share Posted November 23, 2020 thanks guys here's the pics Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted November 23, 2020 Report Share Posted November 23, 2020 (edited) Dremil Time . Edited November 23, 2020 by MikedaddyH Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 23, 2020 Author Report Share Posted November 23, 2020 9 hours ago, MikedaddyH said: Dremil Time . you sure it's not "OK" like the bottom right one lol? Quote Link to comment Share on other sites More sharing options...
MikedaddyH Posted November 24, 2020 Report Share Posted November 24, 2020 It will work but... I little help at the bottom of the upper receiver would improve the feeding of Ammo. Just get it started and match it to the feed ramps of the barrel extension. Do Not get carried away. Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 24, 2020 Author Report Share Posted November 24, 2020 (edited) 12 hours ago, MikedaddyH said: It will work but... I little help at the bottom of the upper receiver would improve the feeding of Ammo. Just get it started and match it to the feed ramps of the barrel extension. Do Not get carried away. any recommendations on dremel bit type? This is 6061 I believe, thinking either a metal cutting type bit or a rounded cone shaped grinder bit might be the easiest like 952 below? Left as is those receiver edges are likely to hit/dent the brass even if it feeds fine right? Edited November 24, 2020 by GT8888 Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 24, 2020 Author Report Share Posted November 24, 2020 (edited) And now I'm thinking what happens to the soft, non-anodized 6061 where I grind it with cases possibly hitting it repeatedly. Since this is to be a 12.5" barrel .308 range toy and not a critical-use tool maybe I should just build it first and see how it runs before taking an irreversible step? Edited November 24, 2020 by GT8888 Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 24, 2020 Report Share Posted November 24, 2020 Pump the brakes my man! I cant see your pics for some reason, but get a 3rd or 4th opinion before permanently cutting into important stuff. Is this gun assembled yet? Has it been fired? Also...mikedaddys first instinct is always dremel 😄 Quote Link to comment Share on other sites More sharing options...
DNP Posted November 24, 2020 Report Share Posted November 24, 2020 (edited) I don’t know....I think dremel doesn’t come into play until after cordless hand drill in his lineup. Edit to add - I can’t see his photos either from the iPhone. Edited November 24, 2020 by DNP Quote Link to comment Share on other sites More sharing options...
blue109 Posted November 24, 2020 Report Share Posted November 24, 2020 (edited) So mike probably cant see the pics either and just wants this poor gent to start grinding away on his gun lol. @GT8888 did you use the upload function to add pics directly from your gallery? Im not seeing them. Just hit the little paperclip and it should let you select pics to add. Edited November 24, 2020 by blue109 Quote Link to comment Share on other sites More sharing options...
DNP Posted November 24, 2020 Report Share Posted November 24, 2020 I was going to say something when I couldn’t see them, but figured it was just my stupid phone. Thanks for confirmation. Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 24, 2020 Author Report Share Posted November 24, 2020 (edited) try these for the pics https://drive.google.com/file/d/1ogrnDx3uDthDjammKUWq55BTlWVio7iV/view?usp=sharing https://drive.google.com/file/d/1ojri-bACjam1WShck7_UdWOCbu4UzULv/view?usp=sharing https://drive.google.com/file/d/1or8gzESLJeE2WRLBO6r0Yjtu9okybVfy/view?usp=sharing https://drive.google.com/file/d/1osCsnyE8Lb4s0y_9CSSx1waUpYfQsjxj/view?usp=sharing https://drive.google.com/file/d/1osM9J3V4EhSsaD5NSVmYy63_ybFnxnfx/view?usp=sharing Edited November 24, 2020 by GT8888 x Quote Link to comment Share on other sites More sharing options...
DNP Posted November 24, 2020 Report Share Posted November 24, 2020 Agreeing with the dremel. It won’t take much. Just blend those ramps in to the receiver. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 24, 2020 Report Share Posted November 24, 2020 Check and see where the magazine presents the round, might be high enough that you don’t have to worry about the receiver ramps. Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 24, 2020 Author Report Share Posted November 24, 2020 looks like ot protrudes slighty above the PMAG Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted November 24, 2020 Report Share Posted November 24, 2020 7 hours ago, GT8888 said: maybe I should just build it first and see how it runs before taking an irreversible step? That's what I would do, get some rounds down range and see if it is an issue before grinding on it. Quote Link to comment Share on other sites More sharing options...
DNP Posted November 24, 2020 Report Share Posted November 24, 2020 Bah...where’s your sense of adventure? If you grind it...it won’t ever be an issue. It might not ever be an issue as it sits...but I vote “won’t” over “might not”. It’s your machine and you can definitely build and run it before deciding. That won’t hurt anything to go that route. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted November 25, 2020 Report Share Posted November 25, 2020 That combo meets "the okay" category, so build it and fire it up first. If you need to get into matching the lower to the feed ramps that the barrel extension has, then use the "Dremel Chainsaw Sharpening Bit." Every Ace Hardware that I've ever been in carries these things. It looks like this: It's an easy task to perform, as the soft(er) aluminum will give way to your efforts, long before that steel barrel extension will - there's little worry of jacking up your barrel extension, if you pay attention to what you're doing. Fear not, if you take that course of action. Obviously, you'd pick another product and polish those nice new feed ramps that you put in your upper, so again, little fear of having projectiles smashing into rough-cut aluminum. Think it through - it's a very simple task. Quote Link to comment Share on other sites More sharing options...
COBrien Posted November 25, 2020 Report Share Posted November 25, 2020 (edited) I don't have much to add re: feed ramps, but... I notice that's a Gibbz (or Gibbz-type) upper. BEFORE YOU GO MODIFYING IT, check your headspace. I have a Gibbz upper in my junk drawer because the upper -- for some reason -- wouldn't allow a perfectly good bolt (as checked by Criterion) to headspace correctly on a Criterion barrel, with the bolt installed in the carrier. Take the bolt out of the carrier, and no issues. Also, search around here for Gibbz and read those threads. I can't recall exactly all the problems others have had, but they're numerous. Edited November 25, 2020 by COBrien Quote Link to comment Share on other sites More sharing options...
edgecrusher Posted November 25, 2020 Report Share Posted November 25, 2020 2 hours ago, COBrien said: I don't have much to add re: feed ramps, but... I notice that's a Gibbz (or Gibbz-type) upper. BEFORE YOU GO MODIFYING IT, check your headspace. I have a Gibbz upper in my junk drawer because the upper -- for some reason -- wouldn't allow a perfectly good bolt (as checked by Criterion) to headspace correctly on a Criterion barrel, with the bolt installed in the carrier. Take the bolt out of the carrier, and no issues. Also, search around here for Gibbz and read those threads. I can't recall exactly all the problems others have had, but they're numerous. This! You never mentioned brand but if it’s a Gibbs good luck Quote Link to comment Share on other sites More sharing options...
GT8888 Posted November 25, 2020 Author Report Share Posted November 25, 2020 Thanks for all the help guys. I headspaced with bolt only with barrel removed and then headspaced with bolt in carrier with barrel installed, probably at least 3 times OCD I guess I may have to try again since you brought it up lol finished it up more or less, haven't checked if it feeds but otherwise seems to operate correctly Quote Link to comment Share on other sites More sharing options...
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