User Panel
Posted: 3/1/2006 10:30:04 AM EDT
If I "ramp" the carrier can I use the 223 hammer? Can I use the M16 hammer in my m16?
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google puts his link first on the list. |
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Is the factory RRA 9mm bolt a full auto bolt? It looks like there is enough room to trip a sear.
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there's a picture on his website showing a full auto carrier, that is what i used to compare.
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I'm also interested in this. His website says that he does not do this work on semi auto carriers. Does a semi auto carrier need this??
scottMO |
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Forgot -- M60JOE |
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Lots of good info. Do semi auto guns need this or is this mainly for F/A?
I've got a Oly Arms k9GL (Glock lower) and it shoots great but every now and then I see one of these posts and it gets me thinking that I need this done too? Do people do this on RRA/Bushmasters 9mms (goes back to the FA/semi question?) scottMO |
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I just put my RRA together today and I ramped the bolt...took about 5 min on my mill. I ordered the upper from Eagle and they were out of 9mm hammers so i figured why not. i just did it so I could keep the stock hammer, and swap uppers.
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BTT
Pic changed, text edited, and text added in my previous post above... hopefully clears things up a little better. |
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Could you please provide specific dimension for the ramp ( length and depth of ramp ) . Pic with dim would be awesome. Are the dimensions of the ramp critical ( +-.010 for example ) I can't have m60joe do it because I'm in Canada and it is a huge PITA getting guns stuff back and forth over the border Since I have a machine shop at home I figure I'll do it myself Thanks |
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I'm having mine machined as we speak at a local machine shop. I will get you the dimensions hopfully by Friday.
IIRC, the angle was 1.93 degrees and a total of .125" was machined down at its deepest point. But wait until I get the specs before you go and send yours off. |
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nothing on the ramp is critical dimension wise. I just held the bolt by the carrier key and put a .5" spacer under the rear of the bolt to get the angle..i went deep enough to take out both catch slots on the bolt. I could of used a smaller spacer as the angle was a bit steeper than it needed to be. if i get a chance i'll post a pic of the bolt in the vise. honestly you could use a dremel if you wanted to(i wouldn't recomend it though). all your really doing is taking the "nub" off the bottom of the bolt and smoothing out the transition. |
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ok here's the bolt in the vise
http://img.photobucket.com/albums/v695/jar944/bolt-setup.jpg and 2 pics of the ramp http://img.photobucket.com/albums/v695/jar944/bolt2.jpg http://img.photobucket.com/albums/v695/jar944/bolt1.jpg like i said it's easy and none of the dim's are critical...as for the original question of using a 223 hammer w/ a ramped bolt...it worked fine for me |
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In regard to this pic---
I LIKE IT !!! That more so duplicates the ramp/shroud as seen on the M16 carrier or "enhanced AR-15" carriers of late.... The std 223 hammer should be fine there, since it finds the bottom of the bolt sooner, as opposed to the longer ramp done by others.. hence the need for the hammer with round face. Very good. |
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for anyone that really needs numbers to work off of...
angle of bolt when milling ramp 5.2* depth of cut .135" the bolt was held in a 6" vise by the carrier key with a .5" spacer under the rear of the bolt (see previous pic) this will give you approx a 5.2* angle |
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Heres what I did. Take your bolt to a machine shop. Show the toolmaker a carrier from a M16/.223... SIR. Make my 9m.m. bolt (ramp angle) match this one. It's kinda hard Maybe a carbide endmill is needed? What kinda beer do you drink? I got mine ramped for a case of M.G.D. ! THEN. Use a M16 fire control group, If your N.F.A. (AR15/.223 if your not). Get an A.A.C. rate reducing buffer. Get K.N.S. trigger/ hammer anti walk pins as well. You can then swap uppers. No other mods needed. Except the 9m.m. magblock. Colt has made some mistakes with this design. This helps to get the bugs, broken hammer pins ETC. remedied. BUT, don't expect this baby to purr like a STEn. They wiggle way more on full than my MK.2. If this scares you call M60 JOE. Your pal, OTTO !!
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I used carbide. I don't think you would even want to try HSS |
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Don't matter to me, not going to make it work anybetter. |
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Nope, too much oil debris blown around from back draft into the upper, I do not store my rifle out in the elements for extended periods of time. Even if it was refinished, it would wear/polish coating off over time due to hammer face riding surface, look at the face of your hammer if it is well used, see a couple shiny spots ? Un-needed added expense for me. |
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Ok, got the bolt back today. The dimensions are 2.5 degrees and the deepest part of the milling was .125". The ramp length is 1.6" I will follow this up with a photo diagraming the specifics tomorrow.
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Thats about what I thought the standard 9mm ramp would be. It's about half the angle I used on mine. what hammer do you plan on running?
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But why should the 9mm bolt be ramped further back than the 5.56mm bolt carrier? Why is only ramping to duplicate the 5.56mm bolt carrier not sufficient? I know the difference between the 9mm blowback versus the 5.56mm delayed recoil could be a consideration, but I see no reason why the amount of travel required to cock the hammer should be different. I know this is what you do for a living, that is why I am asking. I am also considering that people have posted about promlems associated with there bolts being ramped back so far that problems arise.
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The slower the hammer is re cocked the better it is for the hammer pin and hammer pin holes in the receiver. If you use a M16 hammer (or a M16 hammer with the lug removed) what problems? If you ramp the bolt passed the red line (in the pic above) yes you will have problems. The end of the hammer rides on the bottom of the bolt. The bolt can't push the hammer down any farther to get re cocked, it just rides on the bottom of the bolt. That's why the notched hammers usually do not work. They do not get pushed down far enough. Ramp the bolt way less and use a notched hammer and the hammer gets thrown back so fast it will re cock the hammer fine. Way more stress on the hammer pin and pin holes for M16 use in my opinion. The .223 bolt/carrier set up pushes the hammer @.027" down farther into the receiver than the 9mm bolt. That's why the notched hammer doesn't always work with the longer ramped 9mm bolt. 223 and 9mm bolt bottoms: |
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Joe, let me share my thoughts about bolt ramping with you and see what you think. First, I find that ramp length is really unimportant because the cocking of the hammer (hammer reset) happens long before the top of the hammer touches the ramp. Maybe it is just peculiar to my setup, but ramp slope or length is practically irrelevant. I am using a DPMS hammer with a ramp depth of .125" deep (or .078" deep relative to the ramp) at an angle of 2.5 degrees. This puts my ramp overall length at about 1.7 inches which falls short of the red line you used in your example (end of hammer travel which is about 2.077"). Anyway, below are photos illustrating my example. The red line shown below is the same spot as depicted in the next photo below where the two red lines intersect. Below is the bolt in place in relation to the hammer and ramp. Where the two red lines intersect is where the ramp begins. The ramp is milled to an overall depth of .125" (.078" deep relative to the unmilled ramp on the bolt). The next photo illustrates the hammer position in relation to the ramp at the point of trigger and hammer reset (hammer is cocked during recoil). My hammer is reset (cocked) long before the top of the hammer touches the ramp during recoil.
I think that depends upon the hammer you are using. I measured a RRA 9mm hammer and found that it is shorter than my DPMS hammer by .100" (1.5" vs 1.6" measured from center of pin hole). Without a doubt, hammer length will affect performance. My DPMS M-16 style hammer affords me lots of reset based on the longer length.
I did a few calculations to further explore this issue because the guy who I sent my bolt to screwed it up. I am forced to re-ramp the bolt at a shallower angle (which will make the ramp longer) to remove a gouge that was put in my bolt ramp because the guy incorrectly calculated the wrong angle. Anyway this is what I came up with........ The difference between the depth where the ramp would stop at 2.077" (which is where the hammer travel stops) and a ramp length of 2.8" (about the end of the bolt) will only make the ramp .020" deeper at the point where hammer travel stops (at 2.077"). .020" is not a lot and the extra push down on my hammer is not needed anyway. As you can see from my second picture from the top, my hammer is resetting at about 3/4 of the way up the hammer face. I really don't need much more push down on my hammer than what I am getting at 3/4 travel up my hammer (because that is the point at which it gets reset). Joe, before I finish here I just wanted to say that I am a fan of your work. Your .22 Ciener speed loader design inspired me to make my own. It turned out pretty good, but not as nice as the ones you make. I wish that I had sent my bolt to you in the first place, because then it would have been done right. Instead a local machine shop goober screwed my bolt up and left me with a bunch of calculations as to how to fix it. Anyway, I look forward to hearing your input about my observations. Thanks |
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Your hammer might have cocked fine, but, in a M16, the hammer must be pushed @.140" deeper for the auto sear to grab the hammer lug. 2-3 bolts of the 120+ I've ramped didn't work in the M16. I was asked if I ramped the bolt to far. I made the picture so guys would understand that I didn't. I had them file a few thousands off their auto sear (or hammer lug) and all was fine.
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Ah, ok, so the difference is for the auto sear to work as opposed to a semi-auto configuration. Thanks, that makes a little bit more sense. |
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I have a question. If the ramp was cut similar to standard M16 carrier then how would this cause more stress on the pin and holes? I can see it causing more a bit more stress than a long 9mm ramp but I dont understand how it would cause more stress than the M16 carrier. Unless you also ramp the M16 carrier to match the longer 9mm ramp. |
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What bolt do you recommend for a M16 lower and 9mm upper to engage the auto sear? Or do you recommend modifying the auto sear to match the particular bolt you may be running? |
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What's wrong with MtDew's Carrier? It's exactly like a M16 carrier?
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Maybe I didn't make myself clear. I'm stating the longer the ramp the longer it takes to re cock the hammer and there for the less stress on the whole system. |
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I haven't seen any 9mm bolt that wasn't manufactured correctly. I think the issues with the particular guns I stated above was a stack up of tolerances and/or wear on the guns didn't allow the hammer to be pushed low enough. |
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Absolutely nothing. But, depending on the gun set up, the .223 could be running slower than the 9mm blow back and then more of a ramp would be beneficial to slow the speed of the hammer. |
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I have a brand new Bushmaster 9mm bolt carrier along with the Carbon 15 9mm upper that it came with and so far it does not seem to push the hammer down far enough to catch the auto sear but it will catch the trigger assembly. So it works fine in semi but not in auto. In auto the hammer follows the bolt carrier. I have only tested operation without firing, moving the parts by hand, testing engagement. I was thinking a $35.00 auto sear or a $150.00 9mm bolt carrier, then I machine the auto sear before I buy a new bolt. But I still don't like that option. Any ideas? What would you recommend? Do you sell the correct 9mm auto bolt carrier? |
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I would either modify the hammer lug or the sear. My vote is the hammer lug. Grind a little off at a time until the auto sear engages. Either method will not hurt you in any other configurations (uppers) as long as you do it a little at a time until it works. I haven't seen a bushmaster 9mm bolt (that I know of). I hope they made it like the Colt (RRA, Garrison MFG... etc.) I've had guys wrap the hammer (carefully where the hammer slides on the bottom of the bolt) with black tape a few wraps at a time. Then see if the added thickness in tape fixes the problem. Hand cycle, the tape won't last long. If the tape works, you can see that not much is needed to come off the hammer (or sear). |
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With regard to that information about ramping and hammer cocking that seems to suggest this is unneccessary, I would just state the obvious- the bolt cocks 300% easier after the conversion. That translates into less felt recoil.
If you are feeling about 6ft lbs less recoil, how many pounds do you think are now not being exerted on that 1/8th inch pin to create those 6ft lbs? The one place this gets interesting is that that extra pressure is technically holding the bolt closed, so how does that effect the blow-back operation of the weapon? is the bolt opening then prematurely? If the ramped settup is clearly superior, why are companies still making non-ramped bolts, when they should all be ramped and the 9mm hammer extincted? |
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Who said that? How about throwing us a quote? |
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This might be a dumb question, so forgive me in advance, but is it necessary to ramp a semi bolt? I am going to buy an RRA bolt for a project, and want to know if I need to have it ramped, or is it necessary at all? I am a noob to 9mm AR's so please excuse my lack of knowledge..........and who could I get to do this? I dont have tools for it
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I think you're missing the point about ramped 9mm bolts. IIRC, the whole point is to make the bolt work with a regular, semi-auto 223 hammer. If it isn't ramped, the bolt carrier motion will eventually beat the normal hammer out of spec. You ramp the 9mm bolt so you can use a regular hammer in your lower, and (conveivably) swap uppers easier. It has nothing to do with recoil. Am I right, guys? (M60Joe?) |
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