hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 Thanks for all the input gentleman! ModMk1 has been made up. I took it for a trial test over the weekend. Video to follow Link to comment Share on other sites More sharing options...
Chris-NZ Posted June 3, 2015 Report Share Posted June 3, 2015 I look with interest as to how it goes. Hope it is a lot better than one a patient of mine made recently. He's a very handy pistol gunsmith, esp 1911s, but has no experience with high powered rifles. Was basically given a 7 Rem Mag and decided to make a can for it. Think he said he used a ?nitrile spacer at the back and on the first shot, it blew out, never to be found. Wasn't even wearing eye protection. I didn't need to tell him how foolhardy that episode was.. Link to comment Share on other sites More sharing options...
hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 I look with interest as to how it goes. Hope it is a lot better than one a patient of mine made recently. He's a very handy pistol gunsmith, esp 1911s, but has no experience with high powered rifles. Was basically given a 7 Rem Mag and decided to make a can for it. Think he said he used a ?nitrile spacer at the back and on the first shot, it blew out, never to be found. Wasn't even wearing eye protection. I didn't need to tell him how foolhardy that episode was.. Aye, you really have to be careful when dealing with stuff like that. Its all too easy to make one small miss judgment for something to go drastically wrong. You'd think i was leaving for war when i told my Mrs i was heading out to try it haha. I am confident in my machining skills and had a solid design that i was sure would work (although i hadn't seen it else where). Since shooting the video i have redesigned some aspects i believe will work better. I didn't db meter it but by naked ear it sounds like a .22hv which i guess is the goal. Link to comment Share on other sites More sharing options...
bradders Posted June 3, 2015 Report Share Posted June 3, 2015 Thanks for all the input gentleman! ModMk1 has been made up. I took it for a trial test over the weekend. Video to follow Ok questions. Now that you have made Mod Mk1, have you entered it on your license? What if it isn't very good and you make Mod Mk2, do you have authority for 2 cans? If you scrap Mod Mk1 do you inform the Feds and get a new variation afore ye make Mod Mk2? A bit of a minefield if you ask me Link to comment Share on other sites More sharing options...
hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 Ok questions. Now that you have made Mod Mk1, have you entered it on your license? What if it isn't very good and you make Mod Mk2, do you have authority for 2 cans? If you scrap Mod Mk1 do you inform the Feds and get a new variation afore ye make Mod Mk2? A bit of a minefield if you ask me I haven't,it technically doesn't exist anymore as it been torn down and the inadequate parts been disposed of. The final version will be a variation on the Orginal (theoretically the same can) When I have a system that works, is identifiable and safe then i will have it issued on to my cert. Link to comment Share on other sites More sharing options...
hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 Excuse the captions, video was originally sent my sceptical friends.(Video Tempoarally removed) Link to comment Share on other sites More sharing options...
baldie Posted June 3, 2015 Report Share Posted June 3, 2015 That is very efficient indeed. What calibre is the rifle ? Link to comment Share on other sites More sharing options...
hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 That is very efficient indeed. What calibre is the rifle ? Thanks Dave, and it's fitted to my 204R Link to comment Share on other sites More sharing options...
andybrock Posted June 3, 2015 Report Share Posted June 3, 2015 Well done, that does work well. Link to comment Share on other sites More sharing options...
hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 Well done, that does work well. One thing i am going to change, if you listen carefully you will hear a slight ring report at the end of the blast?! That is a compression spring i used to separate the blast chamber and the baffles. It got really anoying as i could feel the vibrations ringing through the rifle well after it went off. As a result, im going to change it for a perforated tube that is cut to the exact screwed tight length. Most likely steel but might go with anodised aluminium. In case anyone is interested the mod is 8 inches long (reflex style) 44mm wide (Will skim to 42 upon completion) and weighs about 450g Link to comment Share on other sites More sharing options...
Chris-NZ Posted June 3, 2015 Report Share Posted June 3, 2015 ...I didn't db meter it ..l. Unless you've got an exotic impulse SLM, you won't get anything meaningful in measuring. Just use your ears, and from that video, it seems pretty good! Link to comment Share on other sites More sharing options...
baldie Posted June 3, 2015 Report Share Posted June 3, 2015 One thing i am going to change, if you listen carefully you will hear a slight ring report at the end of the blast?! That is a compression spring i used to separate the blast chamber and the baffles. It got really anoying as i could feel the vibrations ringing through the rifle well after it went off. As a result, im going to change it for a perforated tube that is cut to the exact screwed tight length. Most likely steel but might go with anodised aluminium. In case anyone is interested the mod is 8 inches long (reflex style) 44mm wide (Will skim to 42 upon completion) and weighs about 450g Just as I thought.... You've maybe seen one of the old Manders [new zealand or Oz ] made rimfire mods ? They were a good design and worked well. I,ve often wondered why an internal recoil spring and blast baffle was not more widely used...it certainly works. Link to comment Share on other sites More sharing options...
hunter686 Posted June 3, 2015 Author Report Share Posted June 3, 2015 Unless you've got an exotic impulse SLM, you won't get anything meaningful in measuring. Just use your ears, and from that video, it seems pretty good!Just a one I have on my iPad, I'm a perfectionist and I know the best I'm a looking at is around 130Db so it was more curiosity to see how far off they mark I was and if it was worth while to keep developing or just to stick with what i have. It's the hand loader in me Just as I thought.... You've maybe seen one of the old Manders [new zealand or Oz ] made rimfire mods ? They were a good design and worked well. I,ve often wondered why an internal recoil spring and blast baffle was not more widely used...it certainly works. I haven't! I had quick gander in the google to find some internal pics but to no avail. My two cents regarding the spring and why people don't tend use them In my very limited personal experience 1: I think people a put off but the "weight" when a slightly better design will solve the problem without the extra grams. 2: You have no idea how bad the ping off the spring is behind the rifle. My best example is it feels like the old Weihrauch HW77 springer air rifles. Kills the charm of a moderated small cal Link to comment Share on other sites More sharing options...
Chris-NZ Posted June 4, 2015 Report Share Posted June 4, 2015 Just a one I have on my iPad, I'm a perfectionist and I know the best I'm a looking at is around 130Db so it was more curiosity to see how far off they mark I was.. OK, to be slightly more clear on this, the number of dB your iPad comes up with will be completely meaningless as the integration time of basic SLMs means they cannot capture sharp impulses. A rifle report has a rise time of a couple of milliseconds, far too quick for your toy SLM to capture accurately. You will obviously "measure" a number but it cannot validly be compared to known damage-risk criteria. In case you're wondering, I'm a clinical audiologist Link to comment Share on other sites More sharing options...
hunter686 Posted June 4, 2015 Author Report Share Posted June 4, 2015 OK, to be slightly more clear on this, the number of dB your iPad comes up with will be completely meaningless as the integration time of basic SLMs means they cannot capture sharp impulses. A rifle report has a rise time of a couple of milliseconds, far too quick for your toy SLM to capture accurately. You will obviously "measure" a number but it cannot validly be compared to known damage-risk criteria. In case you're wondering, I'm a clinical audiologist ....can i borrow your Sonic SLM then? ;-). I wasn't looking to write a theses on the matter it was really just as a loose comparison between the raw sound and the moderated effect. Idle on the meter in a quiet room was around 35Db so i knew from the beginning it wasn't going to be a scientific test, either that or my tinnitus was masking i didn't know about Link to comment Share on other sites More sharing options...
Chris-NZ Posted June 4, 2015 Report Share Posted June 4, 2015 If your meter was reading plain dBSPL or was on C weighing, it's easily possible your "quiet room" has a fair bit of inaudible very low frequency sound. With regard to measuring the difference between std and mod'd reports, your meter may tell you there was say 26dB difference but if there is a difference in the shape of the sound envelope (and there almost certainly will be), your relative difference will even be wrong, let alone the absolute level. It's the peaks that do the damage to hearing. Link to comment Share on other sites More sharing options...
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