Alright guys, another unusual question from me. Is it safe and feasible to take a very light load of a suitable powder ( Nobel sport vectan lowsonic say), and load it into a suitable cartridge, such as a 76mm Fiocchi with a 616 primer, load a suitable heavy slug such as the Brenneke magnum, roll crimp and with the aid of a chrony set the speed to something like right?.
I'd like to make a subsonic/light load, for low disturbance humane dispatch from a hushpower shotgun, as its this I was granted them for but I'm also allowed to 'test' them for these reasons.
Well as people do this with normal birdshot loads, I assume it is doable, but there are a few things that niggle me:
1) Should a high power or low primer be used for this?. As I can get either in 76mm.
2) The roll crimp will be longer/deeper than normal as there will of coarse be much less powder in the case. Will this cause any pressure or other probs?. The slugs are designed for 76mm, would 70mm be better for this or is the crimp depth a non-issue?.
3) Deciding what charge to go for first. I would 'work up' from the small/safe starting amount, presumably anything subsonic will be well within pressure limits so I will chrono them to get them around the right speed.
Obviously this is dodgy territory, as its not like metallic where you can keep an eye out for problem, it just goes bad before you know, which is why I want to seek thoughts from those more knowledgeable first. Anyway its just an idea for now. It does seem logical to me to have a quieter option for this task if ever required so its not just for kicks. Thanks
Could you get over the powder volume problem by using something bulky like Trailboss?
In saying yes to this air rifle you are confirming that you are not a messer and are allowed to go out in public without your carer
Thats the sort of info and ideas I'm looking for cheers, so its a good low speed or pressure powder?. Ideally I think it needs to take up about the same amount of space as 30grains of TechnaN, or 35grains of N350.
It's not for long range so why not just use large shot and a standard subsonic recipe
Are there any standard/official ones though, or just ones we've made ourselves?. If not I may as well make my own, to my own preferences/requirements if possible.Originally Posted by sitsinhedges
It's not for long range so why not just use large shot and a standard subsonic recipe
I produce all my subsonics in 20gauge using 14-17 grains of Vectan A1 depending on what speed I want between 1000-1150fps I use a fibre wad and CX2000 primer and drop foxes cleanly at 20ish yards with 28grams of no6 shot to give you an idea of how effective they are. Change that to BB's and nothing would walk away at close range. Always verify data
Generally you want a fast powder recipe that is at the top end of its range then drop it a couple of grains to get a shell that still develops consistent decent pressures but pushes the shot out at a bit slower.
subsonic for dispatch I use 32g 6# hushpower cartridges which are fine and dont exit so very safe for tarmac bounce!
I know that 14 grains of trail boss fills a .308 case to the bottom of the neck and only produces around 1400fps with a 110 vmax in a short barrel.
In saying yes to this air rifle you are confirming that you are not a messer and are allowed to go out in public without your carer
sorry, lowsonic is way too fast, you`re barking up the wrong tree with that one.Alright guys, another unusual question from me
I'd like to make a subsonic/light load, for low disturbance humane dispatch from a hushpower shotgun, as its this I was granted them for but I'm also allowed to 'test' them for these reasons
Well as people do this with normal birdshot loads, I assume it is doable, but there are a few things that niggle me:
1) Should a high power or low primer be used for this?. As I can get either in 76mm.
2) The roll crimp will be longer/deeper than normal as there will of coarse be much less powder in the case. Will this cause any pressure or other probs?. The slugs are designed for 76mm, would 70mm be better for this or is the crimp depth a non-issue?.
3) Deciding what charge to go for first. I would 'work up' from the small/safe starting amount, presumably anything subsonic will be well within pressure limits so I will chrono them to get them around the right speed.
Obviously this is dodgy territory, as its not like metallic where you can keep an eye out for problem, it just goes bad before you know, which is why I want to seek thoughts from those more knowledgeable first. Anyway its just an idea for now. It does seem logical to me to have a quieter option for this task if ever required so its not just for kicks. Thanks
why 76mm case? if its a low volume powder load, then a 70mm "may" do.
what slugs are you on about? magnum ones? why use a magnum for such short range, BBs in a normal subsonic or light slug
will do. i`d be more enclined to load up some SG at subsonic speeds. it would seriously be better and only s2 ammo.
even subsonic loads can be over pressure. so working up a load would be VERY DANGEROUS.
please NO.
if you really want to load subsonic magnum brennek slugs, stick with a recipe like the tecna, and have downloaded speeds by loading less powder. at some point it wont burn right, that may be after or before the charge that breaks the sound barrier.
i just dont know. however, you are on the right tracks with the 40g slug load. it needs a big belt of powder to get that shifting.
Good deal, Paramainiac 20-05-07
Good deal, Snipperuk 11-09-10
Good deal, Skygrowler 13-10-10
ok, lets sort out this then,
http://www.siarm.it/product_info.php...roducts_id=538
this is a magnum slug, 40 grams, in a 70mm case.
there are some things that are most important here..
first 2.00 grams gets alot of pressure, 888 bar. that is seriously one very hot cartridge. infact its too hot. for me, its just too hot to handle. 12,879 psi where the maximum for 12gauge is 11,500psi and 12gauge 3.5" 14000psi. so is seriously hot.
so for that pressure it tells me the load is alittle stressed, 435ms is 1400fps, so essentially the cartridge has been loaded to 1400fps and then left. so at that pressure, downloading it will have an effect. the tecna charge is about 30grains. so reducing it to an estimated 23-25grains will relieve that pressure, drop that speed, there will be a point on reducing the powder where the cartridge performance will drop off. that cartridge performance is the speed.
the data here is littered with typo`s and mistakes, but there is some evidence to back up the loading.
although check your barrel after firing. you want it to clear the barrel. even at subsonic speeds.
also, why you wouldnt want to shoot subsonic SGs is a mystery, as they are cool. even for "humane dispatch" at 10-15 ft i would have thought they would be the ticket. as the shells can be carried around willy nilly. and not have to be locked away all the time.
Good deal, Paramainiac 20-05-07
Good deal, Snipperuk 11-09-10
Good deal, Skygrowler 13-10-10
nice one mate I had no idea Siarm had that info.
I think then I will either not bother and go with normal velocity and known data, or as you say knock back the charge on known data, got to be the safest way, hopefully it will still burn nice.
magnum slug because I thought the most energy could be had a SS speed, and 76mm cases because I already have a load with 616's. Powder was just a rough guess/example, as I'd seen it used for some nobel sport subsonic data, I wouldn’t necessarily have used it which is why I'm asking you guys really.
So if I use these 76mm cases, the extra crimp depth cant be a big no and I guess the high power primers will suit if anything .
with the original load at 888bar, a downloaded cartridge will still burn right. especially when the original is close to insane pressure.
Good deal, Paramainiac 20-05-07
Good deal, Snipperuk 11-09-10
Good deal, Skygrowler 13-10-10
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