Flashooter Posted February 1, 2006 Share Posted February 1, 2006 Fellow Glockers, I need your help! In order to further reduce muzzle flip I want to add some pop holes to my model 35 Open gun that has a KKM barrel/comp. Currently I'm getting a 181 Power Factor (1167 FPS) using a 155 grain bullet with 5.7 grains of Tight Group. No signs of excessive pressure. I know that by adding pop holes I will lose some velocity, so I want to be sure that I can still safely make major PF . My questions are: 1. How many pop holes? 2. How large? 3. Should they be side-by-side in rows of two 4. Should they be single holes one behind the other Anyone that is using a similar configuration. What is your loading receipe? Any and all advice is most welcome. Leo Link to comment Share on other sites More sharing options...
Flexmoney Posted February 1, 2006 Share Posted February 1, 2006 Before you go there, how about trying some HS6 instead of TG? Link to comment Share on other sites More sharing options...
rstandley Posted February 1, 2006 Share Posted February 1, 2006 (edited) flexmoney is right. The HS6 will require more powder, filling the case and should cause enough gas pressure to operate the comp as it was designed. TG is a good limited power, but not so good using a comp. It burns too fast. The slower burning powder will still be burning when it reaches the comp. I personally use 7.0grs. of N340 vv. behind a 165gr. JHP zero. I am using a 6 port stormlake barrell. I am getting a 192 PF. Edited February 1, 2006 by rstandley Link to comment Share on other sites More sharing options...
Flashooter Posted February 1, 2006 Author Share Posted February 1, 2006 flexmoney is right. The HS6 will require more powder, filling the case and should cause enough gas pressure to operate the comp as it was designed. TG is a good limited power, but not so good using a comp. It burns too fast. The slower burning powder will still be burning when it reaches the comp. I personally use 7.0grs. of N340 vv. behind a 165gr. JHP zero. I am using a 6 port stormlake barrell. I am getting a 192 PF. Flex and RStandley: Several months ago I tried 10 grains of HS6 pushing a 135 Berrys bullet through a Stormlake 6 port barrel. It made a PF of around 175, but I did not like the feel of the recoil. I prefer the feel of the 155 bullet, so I'll definitely try the HS6 with a 155 bullet. Thanx Flex and RStandley! I would still like to get input on how to port (drill holes) in the KKM barrel with comp. So, if anyone has experience with this, I would greatly appreciate your input. Leo Link to comment Share on other sites More sharing options...
TimWarner Posted February 1, 2006 Share Posted February 1, 2006 Start small, use a center cut carbide mill. I've seen both the V-style with 8 holes (on a 24 I believe) as well as a single row. Probably start at about .093 or so, close to the end of the barrel. I would start with one hole, and add holes until you get to the back edge of the cutout. Once you have all the holes drilled, work front to back and enlarge them a little at a time. Make sure to check it with some time of standard load, and not a new pet load. That will give you a more definite feel for what's happening as you're working. Link to comment Share on other sites More sharing options...
eric nielsen Posted February 1, 2006 Share Posted February 1, 2006 Go see Hunter. Wes or Chad or Leo can help too if they are there. Wes & I used a 1/8" carbide cutter. You want to drive a lead bullet under the hole location before you drill. Before you do that I'd make sure you can safely make 175-180 power factor because you are going to lose some velocity with the holes. Link to comment Share on other sites More sharing options...
L9X25 Posted February 2, 2006 Share Posted February 2, 2006 Leo, One of the problems that you may have had with your last HS6 experiment was compensator efficiency. If the comp chambers or ports are not properly sized, or efficient, the extra gas built by the slower powder does you no good, and actually does more bad. You need to vent the majority of the gas upward or outward to keep it from exiting the final baffle hole. I have been the route of 10mm major before and know that the slow powders do work in that caliber, if you have a decent combination. We actually had .45 caliber open loads that performed very well at the lower pressures. Catch me this weekend and we can discuss this at length. Leo (the other Leo) Link to comment Share on other sites More sharing options...
Flashooter Posted February 2, 2006 Author Share Posted February 2, 2006 Leo,One of the problems that you may have had with your last HS6 experiment was compensator efficiency. If the comp chambers or ports are not properly sized, or efficient, the extra gas built by the slower powder does you no good, and actually does more bad. You need to vent the majority of the gas upward or outward to keep it from exiting the final baffle hole. I have been the route of 10mm major before and know that the slow powders do work in that caliber, if you have a decent combination. We actually had .45 caliber open loads that performed very well at the lower pressures. Catch me this weekend and we can discuss this at length. Leo (the other Leo) Tim, Eric, and Leo (the 'good' Leo) You all have given me some good ideas to help me get started on the 'pop holes' project! Leo and Eric, I hope to see you both this Sunday if I can fix the magazine catch spring and get the Glock working again. My Thanx to all for your responses! Leo (aka the 'bad' Leo) Link to comment Share on other sites More sharing options...
Flexmoney Posted February 2, 2006 Share Posted February 2, 2006 Just for correctness... They are really know as "Poppleholes". You can read about them at Brazo's site: http://www.brazoscustom.com/magart/short_and_sweet.htm You can likely find some extra info on this forum too, by punching poppleholes into the search function. Link to comment Share on other sites More sharing options...
Brazos Custom Posted February 2, 2006 Share Posted February 2, 2006 Actually, they aren't Poppleholes unless I do them. If someone else does them they can call them anything they want except "Poppleholes". Link to comment Share on other sites More sharing options...
Flashooter Posted February 2, 2006 Author Share Posted February 2, 2006 Actually, they aren't Poppleholes unless I do them. If someone else does them they can call them anything they want except "Poppleholes". Flex and Bob: The explanation and photos of the Short Gun at the Brazo'a link is very informative, but it also leaves me drooling . . . . Thanx for the link and the search suggestion! Leo Link to comment Share on other sites More sharing options...
Brazos Custom Posted February 2, 2006 Share Posted February 2, 2006 (edited) Flex is right about trying a slower powder this link might help you also: 165 power factor The article is about 6 years old but it still applies. Also, if you did not like the recoil with the lighter bullet you might not like ports in the barrel. Ports will make the gun shoot flatter but work the comp less and make the recoil come straight back - to a certain extent this is the same thing that using lighter bullets does. The gun shoots flatter but the recoil is snappier. Edited February 2, 2006 by Brazos Custom Link to comment Share on other sites More sharing options...
Flashooter Posted February 3, 2006 Author Share Posted February 3, 2006 Flex is right about trying a slower powder this link might help you also: 165 power factor The article is about 6 years old but it still applies. Also, if you did not like the recoil with the lighter bullet you might not like ports in the barrel. Ports will make the gun shoot flatter but work the comp less and make the recoil come straight back - to a certain extent this is the same thing that using lighter bullets does. The gun shoots flatter but the recoil is snappier. Bob, I read and printed the article. It's a big help to this newbie! Many thanx! Leo Link to comment Share on other sites More sharing options...
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