Bjay Posted July 4, 2020 Share Posted July 4, 2020 (edited) So if open COMPENSATED gun works better with slower burning rate powder (n350) vs limited which normally faster power n320 etc. Does this mean a compensated 9mm pcc say 8-14" barrel should work better with slower powder or the other way around? I normally see load for pcc with med to faster powder Edited July 4, 2020 by Bjay Link to comment
Kokeman Posted July 5, 2020 Share Posted July 5, 2020 I've used Titgroup, Universal, CSB-1 and Autocomp in my pccs. CSB-1 is what I settled on. It is supposed to be equivalent to Universal on the burn rate chart. Link to comment
Bjay Posted July 5, 2020 Author Share Posted July 5, 2020 12 minutes ago, Kokeman said: I've used Titgroup, Universal, CSB-1 and Autocomp in my pccs. CSB-1 is what I settled on. It is supposed to be equivalent to Universal on the burn rate chart. I do have 4lb of n330 im thinking getting more powder to try.maybe power pistol or w231? Link to comment
Kokeman Posted July 5, 2020 Share Posted July 5, 2020 3 minutes ago, Bjay said: I do have 4lb of n330 im thinking getting more powder to try.maybe power pistol or w231? To be honest I didn't notice much difference with the different powders if they were the same power factor. The CSB-1 was the cleanest of the ones I tried and has great accuracy. And not to mention I has able to get a bunch for $10 a pound. Link to comment
stick Posted July 5, 2020 Share Posted July 5, 2020 Here's my take...I've really only used Titegroup for my PCC's. I have tried 100gr, 124gr, 147gr & 160gr bullets with light charges and with heavy charges. I do have a 14" barrel with a comp pinned and welded. PCC's have three points of contact, pistols have two points of contact. From my experience, I only noticed a difference in how the bolt cycles. Again, I've only used Titegroup, but in PCC's I want a faster powder with a PF around 135-140. The comp is minimal in helping with dot bounce. Hopefully this helps and it wasn't totally off the wall. Link to comment
zzt Posted July 5, 2020 Share Posted July 5, 2020 Long barrels add velocity over what you get with a 5" pistol barrel. The slower the powder the greater the velocity gain. If you use N350 you can expect a 200 fps gain over pistol. If you lighten the charge you may drop into low pressure/incomplete burn territory. I'd use the N320. For minimal dot bounce you tune your bolt/buffer/spring/etc. to your load, or tune your load to your equipment. FWIW, I've found that a 147 at 140 PF gives me almost no dot bounce. Link to comment
LowSpeedHighDrag Posted July 5, 2020 Share Posted July 5, 2020 26 minutes ago, zzt said: I'd use the N320. +1 Link to comment
George16 Posted July 5, 2020 Share Posted July 5, 2020 12 hours ago, Bjay said: I do have 4lb of n330 im thinking getting more powder to try.maybe power pistol or w231? I have used W231 since I bought my MPX two years ago with great success. It was very accurate with my load of 4.0-4.1 Gr of W231. 124 Gr PD JHP @ 1.125” OAL for 135-140 PF. I have shifted to Sport Pistol due to the hype about it. I used the same W231 load with the sport pistol. Almost similar PF but way cleaner compared to W231. You can also use N320. It has the same characteristics of the sport pistol but cheaper. Sometimes, sport pistol had been called the “poor man’s N320”. Link to comment
mrd Posted July 5, 2020 Share Posted July 5, 2020 Anyone tried to get the comp working with typical gassy open powders like 3n37 or 3n38? And light bullets? Or is something like that only advantageous for shorter barrels, like 5-8 inches? Link to comment
Bjay Posted July 5, 2020 Author Share Posted July 5, 2020 25 minutes ago, mrd said: Anyone tried to get the comp working with typical gassy open powders like 3n37 or 3n38? And light bullets? Or is something like that only advantageous for shorter barrels, like 5-8 inches? I got 14.5 pinned brake and plenty n350 and would like to hear it too Link to comment
LowSpeedHighDrag Posted July 5, 2020 Share Posted July 5, 2020 22 minutes ago, Bjay said: I got 14.5 pinned brake and plenty n350 and would like to hear it too When I tried it last year all I got was more recoil, but I'll do an experiment later in the week to see what I can come up with. Link to comment
mrd Posted July 5, 2020 Share Posted July 5, 2020 (edited) 57 minutes ago, LowSpeedHighDrag said: When I tried it last year all I got was more recoil, but I'll do an experiment later in the week to see what I can come up with. I think you need a comp that only has upward ports to feel any difference. And like you say, it should give more recoil, but hopefully more flat recoil and less dot bounce. I'm considering trying with 3N37 and 115 grain bullets (lightest bullets we can use due to IPSC PCC rules), but I'm not having high hopes - especially since I have a 16" barrel... Edited July 5, 2020 by mrd Link to comment
LowSpeedHighDrag Posted July 5, 2020 Share Posted July 5, 2020 16 minutes ago, mrd said: I think you need a comp that only has upward ports to feel any difference. And like you say, it should give more recoil, but hopefully more flat recoil and less dot bounce. I'm considering trying with 3N37 and 115 grain bullets (lightest bullets we can use due to IPSC PCC rules), but I'm not having high hopes - especially since I have a 16" barrel... I keep reading that 9mm doesn't have enough gas to really drive a comp. My barrel is 14.5" + comp. Link to comment
zzt Posted July 6, 2020 Share Posted July 6, 2020 I can't get over how many of you are concerned about 'working' the comp on a 16" PCC. For a 16" barrel a 115gr plated bullet at 1000 fps (pistol nominal) gives no dot bounce. Same with 950 fps. That's 109 PF and 115 PF. Obviously that won't work for USPSA. As you go up if PF, regardless of bullet weight, you get more and more muzzle rise. At some point you begin to get less. The 'general consensus' is that a short stroked PCC shooting between 135 and 145 PF ammo gives the least dot bounce. As I mentioned above, for me that is a 147 @ 140 PF with my 3/4" short stroked 22 oz. bold buffer, slug and spring setup. I'll add I'm shooting a 5.5" barrel with a shroud. Link to comment
Kokeman Posted July 6, 2020 Share Posted July 6, 2020 17 hours ago, zzt said: I can't get over how many of you are concerned about 'working' the comp on a 16" PCC. For a 16" barrel a 115gr plated bullet at 1000 fps (pistol nominal) gives no dot bounce. Same with 950 fps. That's 109 PF and 115 PF. Obviously that won't work for USPSA. As you go up if PF, regardless of bullet weight, you get more and more muzzle rise. At some point you begin to get less. The 'general consensus' is that a short stroked PCC shooting between 135 and 145 PF ammo gives the least dot bounce. As I mentioned above, for me that is a 147 @ 140 PF with my 3/4" short stroked 22 oz. bold buffer, slug and spring setup. I'll add I'm shooting a 5.5" barrel with a shroud. This has got me rethinking comps on PCC. Link to comment
zzt Posted July 6, 2020 Share Posted July 6, 2020 15 minutes ago, Kokeman said: This has got me rethinking comps on PCC. If you want a comp to work without suffering the dramatic increase in velocity a slow powder would give in a long barrel, you want something short with a comp and a shroud to bring it to 16". Think the Tron comp, or one of the newer copies. Link to comment
Bjay Posted July 6, 2020 Author Share Posted July 6, 2020 1 hour ago, zzt said: If you want a comp to work without suffering the dramatic increase in velocity a slow powder would give in a long barrel, you want something short with a comp and a shroud to bring it to 16". Think the Tron comp, or one of the newer copies. So everyone already purchased the 3 horizontal port and sales on them slows down..why dont we come out with another brake 3 vertical..and people will buy it again..really JP? Link to comment
mrd Posted July 6, 2020 Share Posted July 6, 2020 The engineer who made the JP upward port comp claims that he was able to tune the comp so it actually drove the muzzle down. Then he backed off a bit so the gun just kept level. For him and his shooting style, keep in mind. But still... That barrel looks about 14.5-16 inches. No mention about what loads were used, that would have interesting. So... Is that JP comp and their talk about it just marketing bull to make us spend our hard earned money on stuff that don't work? Or...? Link to comment
zzt Posted July 6, 2020 Share Posted July 6, 2020 This is an example of the type of comp I was referring to above. It is easy to tune your PCC for no dot bounce without a comp. However, it is much harder to do do with really light loads. A comp like this on a 10" barrel will help some with dot bounce, even with 115 PF loads. Link to comment
Bjay Posted July 6, 2020 Author Share Posted July 6, 2020 1 hour ago, zzt said: This is an example of the type of comp I was referring to above. It is easy to tune your PCC for no dot bounce without a comp. However, it is much harder to do do with really light loads. A comp like this on a 10" barrel will help some with dot bounce, even with 115 PF loads. These looks like https://brekkecustom.com/index.php/product/pcc-compxtension-6/ I got their 6" on order arriving today Link to comment
DeChristo Posted August 9, 2020 Share Posted August 9, 2020 Anyone tried to get the comp working with typical gassy open powders like 3n37 or 3n38? And light bullets? Or is something like that only advantageous for shorter barrels, like 5-8 inches? I used 3N37 with light bullets like 115gr and had problems with unburnt powder. Had to push PF to 150 in order to get clean burn on MBX PRO.Switxhed down to N320 with PF 130. I am not a rock star, but with my ability, it is eqsier to control it plus these ALU guns suffer with heavier recoil and want to tear itself apart...Sent from my SM-G973F using Tapatalk Link to comment
mrd Posted August 10, 2020 Share Posted August 10, 2020 13 hours ago, DeChristo said: I used 3N37 with light bullets like 115gr and had problems with unburnt powder. Had to push PF to 150 in order to get clean burn on MBX PRO. Switxhed down to N320 with PF 130. I am not a rock star, but with my ability, it is eqsier to control it plus these ALU guns suffer with heavier recoil and want to tear itself apart... Interesting! How long barrel do you have? Did you try to load short to increase pressure and burn? Link to comment
DeChristo Posted August 10, 2020 Share Posted August 10, 2020 MBX is having 14'' barrel with pinned comp to makeUS legal 16'' length. I tried to shorten the OAL but that in turn increases PF and you get same hard recoil that caused some other issues with the gun (like ripping the threads on buffer tube and some other issues). Will try as well with N340 (in Europe one needs to play with what you can get) to see if I can tame the 115s and the dot play. Link to comment
Fasthenk65 Posted August 10, 2020 Share Posted August 10, 2020 I tried 115's with slower powder ( 4,6 gn N350) and several comps (JP, Armanov). For me it isn't worth it. I changed buffer on my JP to Blitzkrieg and after testing a copper plated 124 RN bullet + RS 12 powder makes it nearly flat. Link to comment
mrd Posted August 10, 2020 Share Posted August 10, 2020 (edited) 19 hours ago, Fasthenk65 said: I tried 115's with slower powder ( 4,6 gn N350) and several comps (JP, Armanov). For me it isn't worth it. I changed buffer on my JP to Blitzkrieg and after testing a copper plated 124 RN bullet + RS 12 powder makes it nearly flat. Do you mind sharing the full spec: barrel length, load data, buffer spring and Blitzkrig model? I think all these factors must be in tune for the gun to flatten out. Once we can see some recipies for flat shooting setups we can start to understand how to make the PCC's shoot flat without having to test everything. Edited August 11, 2020 by mrd Link to comment
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