Jump to content

Add a 4th port or bore my current 3?


Recommended Posts

So hey guys, Im not happy with the reliability of my S12 on the low brass, and even FTE with a slug on V-plug setting 2, so I think ive come to the conclusion that I need more gas. Otherwise I need to run on setting 5 pretty much all the time, and even then not totally reliable. So the question is do I bore the three out to .093 or add a forth at .073? For those of you who bored out to .093+, did you experience any worse fouling of the ports than you did before? Right now I am leaning towards boring to .093 because I keep my gun clean anyway, and drilling a hole at 45 degrees into steel isnt exactly an easy task, and it would requie further modification of the gas block so the hole isnt covered. Right now my ports are right up to the edge, and there isnt any room to add another. Thoughts?!

Link to post
Share on other sites

The bolt is polished, Ive shot about 150 rounds through it, it is converted. Even on 1325 fps 1-1/8th shot it was not flawless.....probably 95% reliable on setting 5 with V-Plug, other than a few FTFs, which I believe were caused by the lip in the feed ramp. i havent had a chance to test it yet since smoothing the feed ramp. Either way, I cant think of much else to change besides running alot more ammo through it to wait and see. Personally I dont really feel like having several more shitty trips to the range, which will take months and cost a few hundo in ammo just to "see" if it works. I would rather slightly over gas it now and have the ability to turn it down. As it stands now, I cant even fire slugs on setting 1, or 2 for that matter.

Link to post
Share on other sites

I understand. The extractor slot mod fixed all of my FTF problems. Have you tried that? The feed ramp mod may have helped, you should do atleast 1 more range trip to see if it helped before drilling. That said I understand how it feels to go to the range and have everyone drooling over your gun only to find out it dosent work reliably. I have a 3 port gun that had the same problems you are having. After the feed ramp, extractor slot mod, and lots of ammo it is very reliable, withe no FTF or FTE. Good luck. Try the low recoil spring to help break it in.

Link to post
Share on other sites

My suggestion is to use the factory mag, puck and perhaps even seeing if the stock plug will help. My other suggestion is to shoot it more. I know that's not the quick and easy fix, but it worked for me.

 

 

I just posted this in a similar thread, but it may help here to:

 

When I first got my S12 (a 4 holer), it wasn't really broken in and exhibited some issues with low brass:

http://www.youtube.com/watch?v=dn3EPsvegOE

 

 

I used the lower power recoil spring as well as the reduced power mainspring and that helped. I also polished the hammer face and bolt carrier. The biggest thing I did to remedy the situation though was just to shoot it. After having put (I'm estimating) about 2K rounds through it, I went back to the original recoil spring and it still cycles anything I feed it, including the very reduced power 2" buckshot rounds:

http://www.youtube.com/watch?v=544FSOBxhE0

 

I've used the stock puck, a CHAOS puck, a twister puck and a tapco puck. All were about the same with the twister being a little cleaner, though it was hard to remove and install. I've since went back to the CHAOS puck, which looks like the stock one, only it's made in the U.S.A. The Tapco is similar.

 

Another thing I've done was to try the various plugs out there. I have the Gunfixer, the MD Arms and the new Auto Plug. All work well, though I haven't had the Auto Plug long enough to have tested it much.

 

 

I hope this helps

 

 

 

Corbin

Link to post
Share on other sites

I went back to the factory gas plug. I screwed it all the way in, went to 2 then one full turn more and it made all difference. Just a thought, it worked for me.

 

ETA: You don't have a twister puck in there do ya?

Edited by Rangerguy
Link to post
Share on other sites

I have three holes at .109 and I get a nice little "puck-o'-shit" in the gas block after a couple hundred rounds of birdshot.

 

Basically, I have to clean my gas block every 200 rounds. I don't mind that so much though, now that I can shoot it from the hip... :super:

 

If I were in your shoes, I'd find someone with a drill press and drill a fourth hole or ream out the other three, one hole at a time. You only want what is needed to run the gun. Yes, I still have to use setting 5 on the V-plug with bulk pack from wally world, and no, I haven't yet used setting one on the V-plug successfully, even with 3" slugs. I'd try opening up the "top hole" (I'm talking about the one in the middle) to 3/32" (.09) and then do a couple of drum dumps. It's always taken a few shots for my gun to start to run like it should after any mods, maybe yours is the same way... :unsure:

Link to post
Share on other sites

I understand that your carrier is polished. Are the hammer and carrier PROPERLY reprofiled? A good reprofiling and fair polishing job will do more for resistance reduction than an excellent polishing job.

Edited by evlblkwpnz
Link to post
Share on other sites

3 larger or a 4th?

I would do whatever you are capable of.

If you can add a 4th, I would. If it is easier to drill out the 3 a little oversize, I would do that and not look back.

 

I have always added ports by using a milling machine and an end-mill. I don't know how precise you could get w/ a drill press and drill bit...lot of movement....I 'personally' wouldn't attempt it.

Link to post
Share on other sites

Since I use this primarily for 3 gun, it HAS to run on birdshot.

 

I too did the polish thing, then I did the low recoil spring. It STILL didn't eject 100% due to short stroking. I decided to get into the the gas block and ADD a fourth gas port. I considered the possiblility of enlarging the holes, but I decided that a foruth hole was my better option. Some have argued that 4 small holes may be cleaner than 3 large holes, but I'm not sure if that holds much merit. I do know that enlarging the holes that are already there would mean I would also have to enlarge the hole in the gas block that sits over the ports. When I got the gas block off, I could easily see enough room for the fourth hole in the gas ring mark. I thought this to be my better option.

 

I don't own a mill. I don't own a drill press either. I did mine with a hand drill. It's not hard to do if you use a punch to mark exactly where you want to drill the hole. Then, use plenty of oil. (Cutting oil is the preference, but I didn't have any. So I used regular old engine oil.)

 

The important thing is to use a good drill bit, and go slow. Start the cut strait, then add the angle to the drill. I put a drill bit in one of the existing holes to act as a guide so I could get the angle approximately right. It's not hard to do and it finally started ejecting the bulk birdshot!

 

Good luck.

Link to post
Share on other sites

I understand that your carrier is polished. Are the hammer and carrier PROPERLY reprofiled? A good reprofiling and fair polishing job will do more for resistance reduction than an excellent polishing job.

Or one could have both & a few other little tweaks to make sure some other unforeseen possibilities don't happen... ;)

 

 

 

 

 

 

 

:nothing:

Link to post
Share on other sites

btw, with a good drill bit, a drill press, and making a nice dimple in the barrel drilling straight down to start, it was actually quite easy to drill the 4th hole. Drilling out the existing ones was cake walk. The bit took seconds to go through....This was way easier than I thought it would be. Getting the gas block off on the other hand was not so easy. It took some hard whacking of a rubber mallet using the shelf bracket shown in the gas block removal thread. The other time consuming and PITA was filing out the hole in the gas block. I had to really enlarge that hole quite a bit to prevent the 4th hole from being covered by the block. My only slight worry now is if the gas plug is going to cover the 4th hole, because the plug is meant to work with the stock hole (im guessing), I am hoping I dont now also have to modify the MD-V plug a bit so it wont make the 4th port useless. Im thinking I may have to turn the plug out an extra turn perhpas.

Edited by Torqued
Link to post
Share on other sites

So after doing some measuring, it appears the MD plug is indeed only meant for a stock hole size, so it will cover a bit of my 4th hole, though im not going to mod the plug until I shoot it, even then, Im going to bring my stock plug with me and see how that does. Ive done too many changes now to make any more without shooting it...Im pretty confident it will be fine now anyway.

Link to post
Share on other sites

It'll be fine, look at it like this, even if the V-plug doesn't cover your fourth hole entirely on setting one, you will still have a partially obstructed .93 hole. That's nowhere NEAR the size needed to make the gun function. You'll still be able to "turn off" your gas system if you wish to by using setting one on the V-plug...

Link to post
Share on other sites

It'll be fine, look at it like this, even if the V-plug doesn't cover your fourth hole entirely on setting one, you will still have a partially obstructed .93 hole. That's nowhere NEAR the size needed to make the gun function. You'll still be able to "turn off" your gas system if you wish to by using setting one on the V-plug...

 

I think you misread what I was saying. Even on setting 5, the plug will be blocking at least a portion of the new port I drilled. The reason is because the MD plug is only machined to have account for the stock opening in the gas block. When you machine out the hole to a D shape, like many folks do around here to uncover blocked holes (or make room for another hole), the MD plug will still cover at least part of the hole, but at least the gas should be able to squirt out under the plug where the hole in the gas block has been opened. I guess my point is without making the "groove" in the MD plug larger to accomidate the larger hole in the gas plug, I dont think it will take full advantage of the new hole.

Link to post
Share on other sites

.093 is 3/32. Im not sure why everyone talks in decimals around here, but you get the decimal by dividing the top number by the bottom. The stock hole size for a 3 holer seems to be .078 or 5/64. Essentially the 3/32 is one bit size larger....

A good quality machinists drill bit set will have a .093 drill in it. Some of us actually have those.

Link to post
Share on other sites

.093 is 3/32. Im not sure why everyone talks in decimals around here, but you get the decimal by dividing the top number by the bottom. The stock hole size for a 3 holer seems to be .078 or 5/64. Essentially the 3/32 is one bit size larger....

A good quality machinists drill bit set will have a .093 drill in it. Some of us actually have those.

 

Or this from DeWalt:

 

http://www.toolup.com/dewalt_dw1969_29-piece-pilot-point-drill-bit-set-metal-index.aspx?utm_source=channelintelligence&utm_medium=15053889&srccode=cii_15053889&cpncode=27-440968

 

For about $80.00

Link to post
Share on other sites

It'll be fine, look at it like this, even if the V-plug doesn't cover your fourth hole entirely on setting one, you will still have a partially obstructed .93 hole. That's nowhere NEAR the size needed to make the gun function. You'll still be able to "turn off" your gas system if you wish to by using setting one on the V-plug...

 

I think you misread what I was saying. Even on setting 5, the plug will be blocking at least a portion of the new port I drilled. The reason is because the MD plug is only machined to have account for the stock opening in the gas block. When you machine out the hole to a D shape, like many folks do around here to uncover blocked holes (or make room for another hole), the MD plug will still cover at least part of the hole, but at least the gas should be able to squirt out under the plug where the hole in the gas block has been opened. I guess my point is without making the "groove" in the MD plug larger to accomidate the larger hole in the gas plug, I dont think it will take full advantage of the new hole.

 

 

Oh, well then I'd get with Mike to see how you should go about doing that since some of the settings on the V-plug only open 1/2 of the little cut-out in the plug...

 

I thought that you did the traditional diamond shaped ports with about the same spacing between them as the factory ones...

Link to post
Share on other sites

I understand that your carrier is polished. Are the hammer and carrier PROPERLY reprofiled? A good reprofiling and fair polishing job will do more for resistance reduction than an excellent polishing job.

Or one could have both & a few other little tweaks to make sure some other unforeseen possibilities don't happen... ;)

 

 

 

 

 

 

 

:nothing:

+1

Link to post
Share on other sites

.093 is 3/32. Im not sure why everyone talks in decimals around here, but you get the decimal by dividing the top number by the bottom. The stock hole size for a 3 holer seems to be .078 or 5/64. Essentially the 3/32 is one bit size larger....

A good quality machinists drill bit set will have a .093 drill in it. Some of us actually have those.

 

Or this from DeWalt:

 

http://www.toolup.com/dewalt_dw1969_29-piece-pilot-point-drill-bit-set-metal-index.aspx?utm_source=channelintelligence&utm_medium=15053889&srccode=cii_15053889&cpncode=27-440968

 

For about $80.00

Dewalt has a smaller 'case' of bits for around $30 that has an .093" bit in it. The Dewalt bits are the best that I have tried. Turn them slow and they will last.

Link to post
Share on other sites

.093 is 3/32. Im not sure why everyone talks in decimals around here, but you get the decimal by dividing the top number by the bottom. The stock hole size for a 3 holer seems to be .078 or 5/64. Essentially the 3/32 is one bit size larger....

A good quality machinists drill bit set will have a .093 drill in it. Some of us actually have those.

 

Or this from DeWalt:

 

http://www.toolup.com/dewalt_dw1969_29-piece-pilot-point-drill-bit-set-metal-index.aspx?utm_source=channelintelligence&utm_medium=15053889&srccode=cii_15053889&cpncode=27-440968

 

For about $80.00

Dewalt has a smaller 'case' of bits for around $30 that has an .093" bit in it. The Dewalt bits are the best that I have tried. Turn them slow and they will last.

 

 

Yeah, but this set has every bit you'd ever need at home...

Link to post
Share on other sites

.093 is 3/32. Im not sure why everyone talks in decimals around here, but you get the decimal by dividing the top number by the bottom. The stock hole size for a 3 holer seems to be .078 or 5/64. Essentially the 3/32 is one bit size larger....

A good quality machinists drill bit set will have a .093 drill in it. Some of us actually have those.

 

Or this from DeWalt:

 

http://www.toolup.com/dewalt_dw1969_29-piece-pilot-point-drill-bit-set-metal-index.aspx?utm_source=channelintelligence&utm_medium=15053889&srccode=cii_15053889&cpncode=27-440968

 

For about $80.00

Dewalt has a smaller 'case' of bits for around $30 that has an .093" bit in it. The Dewalt bits are the best that I have tried. Turn them slow and they will last.

 

 

Yeah, but this set has every bit you'd ever need at home...

Maybe at your home.
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Chatbox

    Load More
    You don't have permission to chat.
×
×
  • Create New...