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GT8888

No Feed Ramps on upper?

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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

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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?

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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???

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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.

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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?

aluminum_oxide.jpg

 

1/2" Cut Diam, 1/4" Shank Diam, Carbide Single Cut Cylinder Ball End Burr

Edited by GT8888

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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 by GT8888

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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 😄

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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 by DNP

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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 by blue109

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I was going to say something when I couldn’t see them, but figured it was just my stupid phone. Thanks for confirmation. 

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Check and see where the magazine presents the round, might be high enough that you don’t have to worry about the receiver ramps. 

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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.

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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. 

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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:

Dremel 3/16 in. Rotary Tool Grinding Stone for Sharpening Chainsaw Blades  (2-Pack)-454 - The Home Depot

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.  :thumbup:

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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 by COBrien

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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

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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

20201125_142411.jpg

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