What sort of Can for a .300 BLK AR-15?

[Jamoy1993]

N320 is only marginally slower than N310. Cannot see the benefit of heavy lead bullets in straightpull. Lead is very forgiving in the MV department, and unless you need extra momentum for fullsize poppers or something, just choose something in 123-165gr that feeds nicely.

Cheapness is the key. I can make a 300 blackout round for about 20 pence for the primer and powder. Lead and Cases are free for me. If i were to shoot 100 - 150 rounds of full powered 300 black you are looking at 3x the price if i were to buy comercial bullets for example. Plus we cannot use alot of higher energy rounds at our 25 Meter range so we cannot use supers as the land owner is a bit iffy at the idea of us using high energy rifles for some reason even though our backstop can withstand 50BMG. Its much easier to get heavier rounds sub sonic and a bit more economic on powder.

If i were doing bigger competition i would certainly use super, commercial ammunition anyways as i don't see the point in blowing hundreds on ammo for simple practice and fun.

I also like the idea of sub sonic as something to play around with, project piece as it may. I will be loading super sonics to use at 2 - 300 yards definately but i want something of centerfire caliber to use at the 25 meter range and i dont see the point in getting a lever action as those are not very practical guns to use. I also want to look at starting CSR as well. The only way for me to feasibly practice with my AR-15 is with sub sonics at our 25 m range.

And I m not sure about 310 vs 320. They appeared to be identical looking at the stats but in practice It seems to be much faster than 320 as I couldn't get my Benelli M2 to cycle with 320 up at 27 grains but it cycles nicely on 24 grains of 310 with 24 gram slugs.

So there is more depth to my choice than just required energy. Fun, Economics and Versatility are what spring to mind making my decision.

 

[StoatallyDifferent]

I have an Ase Utra Jet-Z CQB on my .223. It’s good, but it is a heavy bit of kit and the rifle doesn’t feel as well balanced with the mod on. Not sure if they make the CQB model in .30 but it’s worth a look.

 

[Jamoy1993]

I have an Ase Utra Jet-Z CQB on my .223. It’s good, but it is a heavy bit of kit and the rifle doesn’t feel as well balanced with the mod on. Not sure if they make the CQB model in .30 but it’s worth a look.View attachment 410317

Hey, nice gun mate, aye i was looking at these but they are out of production. Its definately on the list! Thanks
My ar is built to be lightweight. My current AR is 3.6 kg with optic unloaded as of current. This will probably be about 3.2 kg Unloaded with Optic when the 300 upper is made. if i can get it the same weight with a mod it will be very maneuverable.



The one in the middle is my straight pull.

 

[25 Sharps]

Hi folks, so ive got a variation pretty much done for a modular 300 blackout upper receiver, barrel and bolt for my current AR-15 in .223/5.56

I want to toy around with sub sonic cast rounds. I have done the math and i can load a single round for about 20 pence a shot (Primer and Powder), ive got loads of brass and lead for free.

I am looking at getting a HQS Slim X, but it says the max rounds per minuite they reccomend is 6 (Which is pretty pants as i do practical shooting and want to use this at ranges where i do this with energy restrictions, maybe 20 - 30 rounds in quick succession dependant on course).

I need something that fits the following criteria:

About 300 quid new
Able to deal with semi automatic fire / doesnt reccomend sticking to 6 rounds / min
Has to be uniformly cylindrical (I am autistic about how cans look )
Black
Has to be about 40mm in diameter, i am going for a tucked suppressor look like the honey badger. I got the Midwest Industries SP Series 15" MLOK Rail over a 12.5 barrel.
Threads 5/8x24UNEF

Jet Z…..

 

[jthyttin]

Its much easier to get heavier rounds sub sonic and a bit more economic on powder.

My point was, you're as good or actually better off with lighter lead bullets in subsonic rounds.

Heavier bullets are only needed to enable adequate port pressure in semi / full auto (you will get to use large amount of slower powder, get decent burn for it and thus maintain pressure at gas port). Lighter bullets equal lighter recoil, there's basically no difference in trajectory up to 100m and so on (POI could differ substantially but that's the job for zeroing).

In your example 27gr N320 vs. 24gr N310, the difference is 12% (depending on which way you calculate it) and if you bumped the N320 load a bit up you'd probly get the shotgun cycling. Or switching to 28 gram slug and/or different wad to give little more resistance for the (progressive) powder burn. It's not a case of "much faster" or "much slower", the difference is miniscule especially in subsonic rifle rounds where you typically use much larger pressure than in shotgun.

 

[Jamoy1993]

My point was, you're as good or actually better off with lighter lead bullets in subsonic rounds.

Heavier bullets are only needed to enable adequate port pressure in semi / full auto (you will get to use large amount of slower powder, get decent burn for it and thus maintain pressure at gas port). Lighter bullets equal lighter recoil, there's basically no difference in trajectory up to 100m and so on (POI could differ substantially but that's the job for zeroing).

In your example 27gr N320 vs. 24gr N310, the difference is 12% (depending on which way you calculate it) and if you bumped the N320 load a bit up you'd probly get the shotgun cycling. Or switching to 28 gram slug and/or different wad to give little more resistance for the (progressive) powder burn. It's not a case of "much faster" or "much slower", the difference is miniscule especially in subsonic rifle rounds where you typically use much larger pressure than in shotgun.

I know, but i want to experiment with quiet sub sonics. This is the whole point of me looking for a suppressor. There also is pressure and lead hardness to worry about. Lighter bullets at sub sonic speeds produce way more pressure than the 230 grain ones. You are talking about 40 - 50k PSI (Which is totally fine and within safe limits) but then the hardness of my lead comes into question way more than the 18 - 20k PSI from 8.5 grains of V N-110 on a 230 grain bullet. Yes i could harden the lead or purchase hardened alloy but that defeats the other point of trying to make the rounds as cheap as possible for maximum volume.

I dont know if you realise but i am not shooting a semi automatic. I dont need my Ar-15 to cycle as im in the UK and we are not allowed to have that much fun!!!

Here is a GRT screen shot of a 230 grain sub sonic loads and 150 grain 300 blk sub sonic load respectively:

 

[jthyttin]

I dont know if you realise but i am not shooting a semi automatic. I dont need my Ar-15 to cycle as im in the UK and we are not allowed to have that much fun!!!

I'm quite sure I realise that, since twice I've written that you don't need heavy bullet in straightpull. You can do whatever you like, it's your rifle and your money. But some additional comments on the issue:

Since you're shooting the bullets from same barrel, the integral of pressure curve will be larger for the heavier bullet (it needs more work to accelerate to given velocity). Your GRT screenshots are comparing apples to oranges (200gr not 230gr lead bullet, to 150gr FMJ bullet, and very different powders).

If N110 doesn't work for, let's say 123gr LEAD bullet, use something in between like 3N37. Or some powder from some other manufacturer. You will find a choice that will give very similar max pressure and MV than N110 with 200-230gr lead.

If you want QUIET, then you want to use maximum safe pressure. Since the integral of the pressure curve is same (when using same bullet at same MV) the higher pressure in the beginning means lower pressure when bullet is exiting. So moderator has a better change for attenuation.

 

[Jamoy1993]

I'm quite sure I realise that, since twice I've written that you don't need heavy bullet in straightpull. You can do whatever you like, it's your rifle and your money. But some additional comments on the issue:

Since you're shooting the bullets from same barrel, the integral of pressure curve will be larger for the heavier bullet (it needs more work to accelerate to given velocity). Your GRT screenshots are comparing apples to oranges (200gr not 230gr lead bullet, to 150gr FMJ bullet, and very different powders).

If N110 doesn't work for, let's say 123gr LEAD bullet, use something in between like 3N37. Or some powder from some other manufacturer. You will find a choice that will give very similar max pressure and MV than N110 with 200-230gr lead.

If you want QUIET, then you want to use maximum safe pressure. Since the integral of the pressure curve is same (when using same bullet at same MV) the higher pressure in the beginning means lower pressure when bullet is exiting. So moderator has a better change for attenuation.

I mean, the data for the 230 grain load is straight from Hornady's reloading manual so thats where i picked it out to start. Alot of manuals don't have any light sub sonic loads hence why I picked one of the closest sub sonic loads to a mould I could buy. If it doesn't work i can always buy a lighter mold I want to play around so it does not have to be 100% success the first time i dabble.

I have a 2kg jug of 310 on order. I will certainly try out sub loads with lighter projectiles using this powder.

I will try out the 230 grain bullets I have as I bought the lee 5r-230 mold as it is marketed for subsonic 300 blackout. Thanks for the info

I also checked GRT, it does say 230 grain? Im confused.

 

[jthyttin]

I also checked GRT, it does say 230 grain? Im confused.

The bullet profile, or whatever term GRT uses, seems to be the 200gr C309-200-R. In property window the weight is given as 230gr. Lee mold for 230gr would be TL309-230-5R.

I've never used GRT but my guess is there might be included bullet library and you or somebody else has tried to modify the C309-200-R profile to match the 230gr Lee bullet. Word of caution, make sure you know which values GRT is using, if you rely on it for load data.

 

[Jamoy1993]

The bullet profile, or whatever term GRT uses, seems to be the 200gr C309-200-R. In property window the weight is given as 230gr. Lee mold for 230gr would be TL309-230-5R.

I've never used GRT but my guess is there might be included bullet library and you or somebody else has tried to modify the C309-200-R profile to match the 230gr Lee bullet. Word of caution, make sure you know which values GRT is using, if you rely on it for load data.

Ah, this is because i put the measurements of the bullet using calipers into that one as a template as GRT doesnt have a template for it. And no i dont 100% rely on GRT for load data. I use it to put known data from reputible sources in, VV, Hornady, Sierra etc in to make sure it "adds up" Then i always start a load ladder low and follow safe loading procedures.

 

[Andy RV]

ASE offer a Blackout specific mod - S SERIES SL6i-BL .300 BLK - Ase Utra

 

[Jamoy1993]

ASE offer a Blackout specific mod - S SERIES SL6i-BL .300 BLK - Ase Utra

I saw this, i wonder what price they have tagged onto it.

 

[jthyttin]

Then i always start a load ladder low and follow safe loading procedures.

Just a note, with subsonics you should usually start the ladder high and advance to lower weights. This assuming the data is appreciably lower pressure than the rifle can take. In some cases, like jacketed bullets with long bearing surface and fast powder, the reverse might be true. But this is not manufacturer published data.

 

[Jamoy1993]

Just a note, with subsonics you should usually start the ladder high and advance to lower weights. This assuming the data is appreciably lower pressure than the rifle can take. In some cases, like jacketed bullets with long bearing surface and fast powder, the reverse might be true. But this is not manufacturer published data.

That is actually very sensible and makes total sense. The data I am working from is for jacketed 230 grain. Thanks for the info.

 

[jthyttin]

I saw this, i wonder what price they have tagged onto it.

The retail is about 500 Euro and you need the Borelock device (flash hider or muzzle brake) that the mod attaches to.

And it's 43mm so thicker than you requested.

 

[Jamoy1993]

The retail is about 500 Euro and you need the Borelock device (flash hider or muzzle brake) that the mod attaches to.

And it's 43mm so thicker than you requested.

I have swapped to a normal length Handguard (10.5) so i now have 2 inch of free barrel to play with as I was getting annoyed with the distinct lack of suitable moderators so this might work.

 

[jthyttin]

The data I am working from is for jacketed 230 grain.

Lead bullet needs maybe 60-70% of the powder compared to jacketed bullet, especially when we're talking about long bearing surface (I can think of only bore rider, not having long bearing surface in 230gr 30cal). Other way around, lead bullets would probly have something like 450m/s MV with same load that jacketed bullet is around speed of sound.

 

[Jamoy1993]

Lead bullet needs maybe 60-70% of the powder compared to jacketed bullet, especially when we're talking about long bearing surface (I can think of only bore rider, not having long bearing surface in 230gr 30cal). Other way around, lead bullets would probably have something like 450m/s MV with same load that jacketed bullet is around speed of sound.

Interesting stuff. I look forward to the chronograph results. I will need to do a bit more reading. Thank you so much.

 

[Jamoy1993]

So ive decided to go with the ASE Jet Z Compact.

Thanks for the help lads