Compensator Modification

[Joe Furrer]

Currently building first open gun (9mm) using an EGW 5 chamber comp. I have turned off the last two holes and was thinking about removing the material between the first and second chamber (closest to the slide) creating a larger chamber like on an Akai. Has anyone tried this or have a recommendation?

[56hawk]

Could you post some pictures? I'm not sure which comp you are talking about.

[Joe Furrer]

This pic is an as new comp. I have already removed the last vertical side port on comp to be used on the gun. I am thinking about removing material between 2 of the chambers.

[GrumpyOne]

I think if you do that, you'll end up with more of a barrel weight than a comp. 9mm mj doesn't produce a bunch of gas to begin with, and with such a large port, there won't be any pressure to hold the gun still while shooting. But hey, that's just my opinion, and its your money, so if you want to do it, go for it... Let us know how it shoots when you are done. We all may be opening the ports....

[CocoBolo]

Grumpy - I keep hearing this less gas from 9 major, well splain me this if my 38S load is 10gr of AA#7 and my 9 Major Load is 10gr of AA#7, where did the gas go to?

That comp in the picture reminds me a lot of the Bedel comp, I don't know that mine being Titanium made any difference but it failed to adequatley perform its function in 38S and I had to resort to Pumping the load up past 175pf and drilling holes in the barrel to get the gun tamed down to decent. I suspect that in 9 major performance would be similar.

My expierments in 9 major with comps lead me to the Dawson DP-2, which IMHO out performed all other comers. It definatley does not conform to the school of thought that smaller ports and a smaller comp work better with 9 major. I went to it after shooting one in 38S and IMHO if it works for 38S it will work for 9 major.

I still have two guns that shoot either 9 major or 38S just swap barrel and comp out, to be honest the 9 major is more plesant to shoot, softer and flater, at the same PF, comprably equipped with a big honking large port comp.

Back to the thread, put that thing on and shoot it before you butcher it any more, if it don't work then try whittling and whacking then if that fails try a Dawson DP-2 or a Jim Hand comp.

[GrumpyOne]

Grumpy - I keep hearing this less gas from 9 major, well splain me this if my 38S load is 10gr of AA#7 and my 9 Major Load is 10gr of AA#7, where did the gas go to?

That comp in the picture reminds me a lot of the Bedel comp, I don't know that mine being Titanium made any difference but it failed to adequatley perform its function in 38S and I had to resort to Pumping the load up past 175pf and drilling holes in the barrel to get the gun tamed down to decent. I suspect that in 9 major performance would be similar.

My expierments in 9 major with comps lead me to the Dawson DP-2, which IMHO out performed all other comers. It definatley does not conform to the school of thought that smaller ports and a smaller comp work better with 9 major. I went to it after shooting one in 38S and IMHO if it works for 38S it will work for 9 major.

I still have two guns that shoot either 9 major or 38S just swap barrel and comp out, to be honest the 9 major is more plesant to shoot, softer and flater, at the same PF, comprably equipped with a big honking large port comp.

Back to the thread, put that thing on and shoot it before you butcher it any more, if it don't work then try whittling and whacking then if that fails try a Dawson DP-2 or a Jim Hand comp.

Coco, that is only one powder. You cannot draw a conclusion that all will work the same. Most of the 9mj shooters I know of are using HS-6. HS-6 takes a lot less than 10 grains. You are in the minority using that chunky, dirty AA #7. Now, that being said, I'd be remiss if I didn't mention that I have a lb or 2 of AA#7 on my shelf.... Comp design depends greatly on what powder and load you are running through the gun. Just like there is no magic bullet, there is no magic comp.

Edited January 16, 2013 by GrumpyOne

[Desmo412]

I tend to agree with Cocobolo. I run 9.1gr HS6 or 10.5gr AA#7 in my 9-Major gun with 115 MG JHPs. Both make a 175PF...the dot rises to 12 o'clock in the lens and returns to center. I can't imagine 38SC being ANY flatter.

That being said, I am going to be sending my gun back to FGW to add a few popple holes to go along with the CCG comp. There's enough room in a case for 10gr or so of HS6, so thats what I want to use

[Parallax3D]

Not shure how well Shay Akai's comps work, (although I hear they work well), but I've always been told that the more ports the better. Every port presents a flat surface for the gas to push against. I know I had my friend make a new comp for my 9mm major gun that had three top and two side ports, as well as bleeder holes on the side, (think of a copy of Brazos Thundercomp.) He made the first port WAY too large, (about 1/2"), and the result was all of the gas dumping out of the first port, and the other ports becoming pretty much useless. He made another comp to replace that one that has four top ports, and two side ports. The ports are all smaller than normal, (3/16" as opposed to 1/4"), and it seems to shoot flatter and softer than before.

[Joe Furrer]

That makes sense to me. I think I will leave it for now and consider side holes in the future.

[CocoBolo]

Grumpy - I keep hearing this less gas from 9 major, well splain me this if my 38S load is 10gr of AA#7 and my 9 Major Load is 10gr of AA#7, where did the gas go to?

That comp in the picture reminds me a lot of the Bedel comp, I don't know that mine being Titanium made any difference but it failed to adequatley perform its function in 38S and I had to resort to Pumping the load up past 175pf and drilling holes in the barrel to get the gun tamed down to decent. I suspect that in 9 major performance would be similar.

My expierments in 9 major with comps lead me to the Dawson DP-2, which IMHO out performed all other comers. It definatley does not conform to the school of thought that smaller ports and a smaller comp work better with 9 major. I went to it after shooting one in 38S and IMHO if it works for 38S it will work for 9 major.

I still have two guns that shoot either 9 major or 38S just swap barrel and comp out, to be honest the 9 major is more plesant to shoot, softer and flater, at the same PF, comprably equipped with a big honking large port comp.

Back to the thread, put that thing on and shoot it before you butcher it any more, if it don't work then try whittling and whacking then if that fails try a Dawson DP-2 or a Jim Hand comp.

Coco, that is only one powder. You cannot draw a conclusion that all will work the same. Most of the 9mj shooters I know of are using HS-6. HS-6 takes a lot less than 10 grains. You are in the minority using that chunky, dirty AA #7. Now, that being said, I'd be remiss if I didn't mention that I have a lb or 2 of AA#7 on my shelf.... Comp design depends greatly on what powder and load you are running through the gun. Just like there is no magic bullet, there is no magic comp.

Grumpy this forum is plastered with my load 7.7gr of Silhouette with 125gr Zero JHP. I've run HS6 but prefer Silhouette. Were not talking about one powder here, the reason I used AA#7 as an example is because folks could relate to the EQUAL amount of powder for major. I've tried a lot of different powders in both 38S and 9 mm, and I tried a bunch of comps designs. Now realize that open is a Division where preference varies a lot. A few N350, 3N37, 3N38, N105, IMR4756, IMR7625, AutoComp, HS7, WSF, BlueDot, Silhouette, TruBlue, HS6, AA#7, and I'm sure a couple more I have forgotten. Not log ago a friend bought an 38S Open gun, he wanted to try powders I sold him all the partial pounds that didn't make the cut. He had a TruBore I figured he would pick N105 of the lot but suprise he picked HS6. Noob. My 38SC load was or is still AA#7 almost as flat as N105 but way cheaper and easier to get, plus N105 slaps the palm a little harder.

This could all be mood point as all threaded barrels could soon be illegal so our only choice for Open 10 will be the Trubore design, which can be made decent with the addition of a couple #3 poppel holes, and some serious milling on the slide. Chunk that fishing weight slide racker as well.

So I'm going to make my point Juan Mo Time, I don't believe, and by that I mean after testing, that a small comp performs better in 9 major. End of statement nothing to add.

[toothguy]

http://www.brianenos.com/forums/index.php?showtopic=116874

[Joe Furrer]

Thanks for the link. Useful information. The comp I am using looks very similar to the one Matt C is using.

[DRichardson]

It's seems like the best place for this.

I have a springer 3 port comp. http://shop.springerprecision.com/product.sc?productId=107&categoryId=34. I have tried a lot of loads (Autocomp, HS6, and Shilhouette with 124 and 115 bullets) and have settled on autocomp under 124's being the best I have found so far. The barrel has a relatively short throat so until I get it reamed I can't do any of the higher volume powders like AA7, 3N37,and 3N38. The dot stays in the glass but won't track completely straight with any load. Will adding some side ports in either the final or last 2 chambers possibly help stabilize the dot? Is there any formula to decide how big they should be or is it all trial and error?

Edited February 17, 2013 by DRichardson