Sean Gaines Posted June 7, 2006 Share Posted June 7, 2006 Here is the situation. I have a .38 Super Trubor STI factory pistol. Is there a difference in recoil by adding some blow holes to the barrel and slide? I also understand that recoil is percieved, but want to hear from guys and gals who have used both. If it noticably flatter, how many should I get and should they be angled forward towards the muzzle end? Also since adding blow holes will require drilling into the slide, should there be concern for rust, on the slide or should the holes be done in conjunction with lets say a hard chrome, or some sort of finish to prevent rust. Also I have seen some other open guns with blow holes added in which they put sort of a cone shaped hole into the slide, and I have also seen where the holes in the slide have been offsetted to compensate for the slide traveling rearward. I guess they do this so the gasses are not blowing underneath the slide. Which way would be the way to go? I guess if anyone out there has done this could you post pictures of your hybrid setup, and any advice would be appreciated. Thanks PK Link to comment Share on other sites More sharing options...
TMC Posted June 7, 2006 Share Posted June 7, 2006 Do a search my friend, try TJ holes, poppel holes, barrel holes. This one has been thoroughly discussed. Link to comment Share on other sites More sharing options...
rtr Posted June 7, 2006 Share Posted June 7, 2006 My open gun has two blow holes in it http://www.brianenos.com/forums/index.php?...topic=28090&hl= They are angled towards the front of the gun I believe, holes go right through the slide and into the barrel. Gun is in the white, has been for almost 3 years, no signs of rust, but I live in a very dry place (Colorado). Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted June 7, 2006 Share Posted June 7, 2006 In addition to your "blow holes" you will need a corresponding 'slot' cut in your slide, not just "corresponding holes". Unless you have a locked breech, like a bolt action, that doesn't move/cycle with recoil a lot of the gases will catch the inside of the slide, eventually causing a lot of trouble. You would do well to consult with a custom 'smith before you turn your drill (shudder) loose on your barrel. Link to comment Share on other sites More sharing options...
Sean Gaines Posted June 7, 2006 Author Share Posted June 7, 2006 In addition to your "blow holes" you will need a corresponding 'slot' cut in your slide, not just "corresponding holes". Unless you have a locked breech, like a bolt action, that doesn't move/cycle with recoil a lot of the gases will catch the inside of the slide, eventually causing a lot of trouble. You would do well to consult with a custom 'smith before you turn your drill (shudder) loose on your barrel. no I don't plan on pulling out the ol craftsman drill for a project like this. Of course I would send it to a smith who has delt with this before. I can only imagine what the underside of a slide would look like if those slide holes were not placed properly. I have seen blast sheilds that look like someone took a chisel to it. So you would reccomend an oval shape cut or slot cut on the slide to ensure that the gases are being released into the air instead of under the slide? I guess that could also act as slide lightning to, although thats not my intent. does anyone have a pic or can take a picture of how thi is supposed to look like Thanks PK Link to comment Share on other sites More sharing options...
gans Posted June 7, 2006 Share Posted June 7, 2006 In addition to your "blow holes" you will need a corresponding 'slot' cut in your slide, not just "corresponding holes". Unless you have a locked breech, like a bolt action, that doesn't move/cycle with recoil a lot of the gases will catch the inside of the slide, eventually causing a lot of trouble. You would do well to consult with a custom 'smith before you turn your drill (shudder) loose on your barrel. no I don't plan on pulling out the ol craftsman drill for a project like this. Of course I would send it to a smith who has delt with this before. I can only imagine what the underside of a slide would look like if those slide holes were not placed properly. I have seen blast sheilds that look like someone took a chisel to it. So you would reccomend an oval shape cut or slot cut on the slide to ensure that the gases are being released into the air instead of under the slide? I guess that could also act as slide lightning to, although thats not my intent. does anyone have a pic or can take a picture of how thi is supposed to look like Thanks PK This is one way. I would recommend a blast shield, and yes it will get hammered. Link to comment Share on other sites More sharing options...
DaG Posted June 7, 2006 Share Posted June 7, 2006 I've had guns with and without holes and can't tell any difference. The only thing I did notice was about 25-30 feet per second difference in velocity. Oh, I did notice the gun was a little louder with the TJ ports. Of course this was ME shooting MY guns.....FWIW DaG Link to comment Share on other sites More sharing options...
blackdragon Posted June 7, 2006 Share Posted June 7, 2006 "Blow Holes" = More powder! Ivan Link to comment Share on other sites More sharing options...
Sean Gaines Posted June 8, 2006 Author Share Posted June 8, 2006 "Blow Holes" = More powder! Ivan adding more powder doesn't bother me, actually I heard a guy tell me to load the rounds hotter to effectively work the comp, don't know how true this is. I just want to know if adding blow holes will keep the gun flatter. The gun shoots sorda flat, but if I can get it flatter I will. I notice that most of the GM shooters have at least a couple of holes in the barrel. It seems to me that if the gasses are being pushed out of the barrel more towards the center axis of the weapon, that it would stabalize it more. I guess correct me if I am wrong. PK Link to comment Share on other sites More sharing options...
blackdragon Posted June 8, 2006 Share Posted June 8, 2006 PK, I have 6 ( 1/16-1/8" Holes) in my open gun Freddy Craig built it for me. Do I notice the difference with the new lower PF. Nope! With the old PF Yep! Yes you need to run a lot of powder to make the gun shoot flater More powder= more $$$. Ivan Link to comment Share on other sites More sharing options...
gans Posted June 8, 2006 Share Posted June 8, 2006 "Blow Holes" = More powder! Ivan adding more powder doesn't bother me, actually I heard a guy tell me to load the rounds hotter to effectively work the comp, don't know how true this is. I just want to know if adding blow holes will keep the gun flatter. The gun shoots sorda flat, but if I can get it flatter I will. I notice that most of the GM shooters have at least a couple of holes in the barrel. It seems to me that if the gasses are being pushed out of the barrel more towards the center axis of the weapon, that it would stabalize it more. I guess correct me if I am wrong. PK Actually, your hand will rise a little. The barrel ports are closer to your hand and will hold it down a bit. Don't expect a lot from a couple of barrel ports though. Link to comment Share on other sites More sharing options...
Shadow Posted June 8, 2006 Share Posted June 8, 2006 To me, the holes definitely make a difference. I've shot the same gun before and after adding two 3/16 holes with the Max Michel spacing, and to me it made a noticeable difference (flatter). 5" gun with Brazos PROsx cone comp on a BarSto barrel. I also don't notice the extra noise. YMMV. Link to comment Share on other sites More sharing options...
blackdragon Posted June 8, 2006 Share Posted June 8, 2006 (edited) Noise, Well that is a different story! Ivan Edited June 8, 2006 by blackdragon Link to comment Share on other sites More sharing options...
BSeevers Posted June 8, 2006 Share Posted June 8, 2006 I didn't put any on the new gun and I don't miss them. Link to comment Share on other sites More sharing options...
shooterbenedetto Posted June 8, 2006 Share Posted June 8, 2006 i heard eric graufel's gun has 16 ports? and his gun is very flat!! i have 2 holes on my open gun 9mm. im loading 8.0g of n350 didn't notice the difference. sucks because i have powder spill everytime. slows down on reloading ammo. Link to comment Share on other sites More sharing options...
Radical Precision Designs Posted June 8, 2006 Share Posted June 8, 2006 There are different ways. Some cleaner than others. Some more elaborate. Some simpler. The sky's the limit ... You can minimize the effects of the "blow holes" by slightly relocating your red-dot (C-More) a little bit to the rear . You may have to drill and tap new mounting holes in your scope base though, to re-mount it farther to the rear. No need to re-do your frame. Link to comment Share on other sites More sharing options...
XRe Posted June 8, 2006 Share Posted June 8, 2006 "Flat", in many ways, depends on your grip and stance, and not on how much comp or how many ports you have on the gun. Also, the whole equation depends quite a bit on your powder choice - you need more gas to work those ports. As long as the hole in the slide is slightly larger than the hole, you should be fine. There's plenty of slow motion video out there that clearly demonstrates that the gas is gone by the time the slide begins to move - here's an example of what I'm talking about: http://www.brianenos.com/forums/index.php?...pe=post&id=2944 Note, too, that in this case, the port is "jetted" (ie, an angle cutter was used to create a nozzle) - you can't do this with a slot.... No, it won't cause slide erosion, yes it works fine. Link to comment Share on other sites More sharing options...
eric nielsen Posted June 8, 2006 Share Posted June 8, 2006 What xre said. Every pistol will move if you don't react to the recoil. Difference between many shooters is how strongly and how EARLY they react to the recoil. If you're timing the gun really really early the gun might appear motionless. Also you're in danger of pulling the gun down before the bullet leaves the barrel [low-left hits or clean whiff on steel]. Blow holes work nice, not nearly as loud as true Hybrid holes, nowhere near the concussion either so you're not as tempted to wear a full-face motorcycle helmet. I don't have any now & I'm pretty happy with my 5-chamber, sideported comp. But holes work. Sideports have a different effect which is softening the recoil - taking some of the slap out of your hand. They vent more of the gas that is pushing the comp baffles. BOTH blow-holes & sidports will work more effectively with more powder. 2 blow-holes will flatten the jump of a 10-grains-of-powder load more than the same 2 holes would flatten the jump if your load is 7.8gr of some other powder. The more I shoot Open the more I think that the gun's behavior [it's personality] is tied directly to how many grains of powder you shoot. So pick the powder and the bullet weight needed to get the powder charge the you "enjoy" shooting. I've already decided I don't like shooting much more than 10 grains, up near 11 grains is really violent. Buddy of mine has an IMM that NEEDS 11+ grains of powder to make Major with a 125 bullet & I suggested he try shooting 135's thru that gun. My preference for a long time has been a load between 9 grains and 10 grains. Also starting to flirt with loads between 8 and 9 grains [imr 7625] which is tempting because the gun pushes UP a little more but pushes BACK a lot less. It's nice for awkward positions and shooting on the move. Try different combinations & see what you like. Link to comment Share on other sites More sharing options...
L9X25 Posted June 8, 2006 Share Posted June 8, 2006 I agree with the theory behind what Eric said but have a few views that differ. I also know that "blow holes" work. The question is whether the improvement in gun feel is worth the extra abuse (noise and blast) that they create. It is a compromise and I go back and forth on the issue. I do not understand the comment that blow holes are not as loud or create near the concussion as a Hybrid ... I think that holes of equal number and diameter are going to create very comparable noise and concussion levels with comparable loads. I also disgree that the number of grains of powder is unit that needs to be kept within a particular range. My light loads are in the 11-12 gr range and I have loads that are in the 18gr range. I personally have settled on a 15 gr load that is my favorite with many of my guns. I am sure that the feel has a great deal to do with the powder involved and less to do with the charge weight. Frequently N-105, 3N38 & N-350 have similar charge weights but very different "feels". Leo Link to comment Share on other sites More sharing options...
spook Posted June 8, 2006 Share Posted June 8, 2006 i heard eric graufel's gun has 16 ports? and his gun is very flat!!i have 2 holes on my open gun 9mm. im loading 8.0g of n350 didn't notice the difference. sucks because i have powder spill everytime. slows down on reloading ammo. Eric's old gun (before the rule that says you have to shoot at least 120 grain bullets to shoot major in IPSC Open) had 4 or 5 big blowholes in a straight line in the top of the barrel (like the S_I Hybrids). Eric shot 115 grain bullets at that time. After the rule came in effect, Eric switched to 124 grain bullets and he also switched to the small V16 ports he currently uses. I know jack squat about Open guns, but I remembered this and thought it might be useful (or not ) Link to comment Share on other sites More sharing options...
eric nielsen Posted June 8, 2006 Share Posted June 8, 2006 (edited) Leo Yes - with your 9x25 guns, the ones with any blow holes scare me. The new one with no holes is really nice. Until you stand next to it anyway. I can't fit 15 grains in my ammo [thankfully] so I kinda skipped over that part. Still think the IMM with 135's and less powder would be nice. Edited June 8, 2006 by eric nielsen Link to comment Share on other sites More sharing options...
L9X25 Posted June 8, 2006 Share Posted June 8, 2006 Eric, I think that the original IMM guns proved that you CAN get too much of a good thing. The newer versions have drastically less porting and still feel pretty good without all of the limitations caused by the massive porting. We actually had an old style IMM in 9x25 for a short while ... where is that full face motorcycle helmet??? Leo Link to comment Share on other sites More sharing options...
PaulW Posted June 8, 2006 Share Posted June 8, 2006 Never forget the first time (and last for that matter) that Leo talked me into trying his 9x255555555. I was getting ready to squeeze a round off and I quote Leo "Oh yea, one more thing; you may want to keep your mouth closed, it's kinda hard on the teeth". My first thought was Awe Sh*t, what have I got myself into this time. Link to comment Share on other sites More sharing options...
shred Posted June 8, 2006 Share Posted June 8, 2006 FWIW, I'm a believer in the 'grains of powder' theory, for Super (I had some great 9x25 loads too, back in the day). It's the mass of the powder gas that works the comp. Velocity & pressure help some too, but it's throwing stuff one way to get stuff the other that does it, and velocity and pressure aren't going to vary by 20% like a charge weight from 7.5 to 10 grains does. Link to comment Share on other sites More sharing options...
spd522 Posted June 8, 2006 Share Posted June 8, 2006 My Major 9 Para has the Trubore S2 barrel/comp and nothing else. I haven't shot anything comparable to it with blow holes. My thought is that is already shoots a lot softer and flatter than when it was originally a 38 Super so I am way ahead in that respect. My Major load with 7.4 Longshot and a 124 gr bullet consistantly gives me a 171 PF, is accurate, and clean. I can change a bit of the felt impulse with a different recoil spring but as for putting more holes up top and then having to change my load and go through that again just to try to obtain a bit more control........... it isn't worth it to me. For me, I figure more practice with the right grip and stance will make a greater difference in my recoil control than milling and drilling on the gun. Cheaper too. Link to comment Share on other sites More sharing options...
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