Lets find a SUBSONIC LOAD for the Grendel that cycles!!

[txgunner00]

It is definitely an investment. We are living in great times as far as suppressors are concerned. LOTs of good, affordable options and more coming out seems like every week. I'm really eyeballing that SilencerCo harvester... Light, relatively inexpensive, quality... And I REALLY want the 12 ga Salvo but it is pricey. However, the sting on the wallet goes away quickly once you start pulling the trigger...

[LRRPF52]

You can Form 1 and build a can for $125 in materials.

[Adam Lilja]

Yup. Full Auto Suppressed Subsonic is definitely fun. MP5SD is like that, but the 300 Whisper has way more energy. My buddy has a 6.5" twist on his barrel, and I think you can consistently launch out to distance with repeatable hits with that set-up. I'm very tempted to go to 300BLK for most of my CQM/CQM training from now on. It also might allow me to shoot pistol steel that isn't rifle rated.

For any of them, I think a tight twist is where it's at. I shot a special custom canned AR10 at BoomerShoot this year that was crazy quiet with M118 supers.

I've got just the barrel for you!

[Sniper338]

Is that form 1 deal still open? I havent checked ot lately... and dont know my username and password right off the top of my head..

[txgunner00]

Are you talking about efile? If so, yes.

I have 10 or 12 stamps now of which all but 2 are form 1s. A while back I decided to invest in a lathe and mill instead of buying the list of cans I wanted. Paid off very well for me. My last .22 can I made I had $10 worth of materials in it.

[Adam Lilja]

Interesting reading the SS hunting experiences of others.

My experience of SS hunting with 300BLK is similar. The animal must be closer than supersonic, 100M, slightly more or less. this means you have to stalk up and expect to miss opportunities if they scarper before you get close enough. While not using muffs the sound of a round that cycles Blackout is loud enough that they hear it at 100, even with a suppressor. The slap of the sound of a SS hitting flesh is also loud and can be heard at the firing point. In all my experience animals in the vicinity of a SS shot will sense something is wrong and scarper.

SS impacts don't have the kinetic shock of a supersonic. I shot one two weeks ago and it hopped around while I mooched around looking for the spent case. By the time I walked up to it it had bled out. I have settled on 220SMK's as they feed reliably and tumble on impact. Best results I have managed to find over a range of bullets. They do not break up, even on bone, just tumble.

You can see the cracked femur in this photo. The round entered the roo side-on at the hips, through to the other side cracking the left side femur and coming to rest just inside the far side skin. First time I've managed to recover a SS round on flesh. They mostly through and through. You can almost reload it.


Agree with others. No point in downloading your Grendel to shoot SS unless you have a suppressor.

Agree also with '52' regarding 9mm MP5 vs. Blackout. The suppressed MP5-SD is quieter than a cycling suppressed Blackout. You are loading three times the powder and twice the weight of projectile in a Blackout than a 9mm and it comes out with more muzzle pressure (sound). You can download something that's similar to a 9mm in the Blackout but it will not cycle the action. For example, a 110gr with 6.2gr of Trail Boss. Nice and quiet but as I said, no cycling.

Having realized noise is critical when hunting SS I'm heading down the dedicated .22L upper path. Lighter, shorter barrel with a smaller suppressor. And much quieter than any larger caliber. Unless you are hunting pigs or deer a .22 at 100M will do the business.

Derailed the thread again, apologies.

.22 LR over .17 HM2 or HMR?

[BjornF16]

A while back I decided to invest in a lathe and mill instead of buying the list of cans I wanted. Paid off very well for me. My last .22 can I made I had $10 worth of materials in it.

What lathe did you get?

How about starting a "How to" thread on making cans?

[Adam Lilja]

Yes, interesting idea.
Just been looking at Bill Alexander's AR offering. Do Subsonic .17 cycle the action?

I don't know, but I imagine if a 22LR does it then a HMR would. HM2 might be iffy

[txgunner00]

What lathe did you get?

How about starting a "How to" thread on making cans?

I have a 26" grizzly I found for a great deal on craigs list. I haven't taken many pics during the process. There's tons of pics on the hide and silencer talk. That's where I got most of my ideas. If I have time this week I'll get a few pics of my projects.

[jluck]

I would be damn careful with reduced charge loads of a "Normal" Grendel powder, I would start with a heavy bullet and slow powders looking for a full shell case. I think I'd start with surplus WC870.

My two pennies....

[Sniper338]

I would be damn careful with reduced charge loads of a "Normal" Grendel powder, I would start with a heavy bullet and slow powders looking for a full shell case. I think I'd start with surplus WC870.

My two pennies....

I was going to post something... but deleted it for the sake of probably too many newbie and intermediate level reloads that may read it that dont need the ideas..

[txgunner00]

I would be damn careful with reduced charge loads of a "Normal" Grendel powder, I would start with a heavy bullet and slow powders looking for a full shell case. I think I'd start with surplus WC870.

My two pennies....

Your concern is valid. "Secondary explosive effect" can happen if your load density gets too low. I won't go into detail why as there is plenty of data out there already. Anyone attempting this project should heed the warnings.

I have tried the full range of powders in the course of this project from pistol powders to H50BMG & US869. The slow powders gave me the most trouble. In several cases I had unburnt powder get back in between the shoulder of the case and chamber wall because pressures were not great enough to expand the brass and create a seal. I will not try them again myself.

Pistol powders worked OK as far as producing fairly consistent SS velocities but didn't have enough port pressure to cycle the action on my 20" barrel. 8208 seemed to be a sweet spot of burn rate, pressure and port location in the 20" but not so much in the 12.5". I get good consistent velocities but not enough pressure to fully cycle the 12.5. It ejects the spent case but doesn't always pick up the next round. I plan on trying faster powders again for this rifle.

One thing we have working in our favor is the relatively small case volume of the Grendel. Combine that with long, heavy bullets seated deeply in the case you can get acceptable load densities even with reduced loads. We can also use 7.62 x 39 brass which increases load density due thicker case walls. I even take this a step further by using only neck sized brass. The result is very little air space in the case with 8208. I measured the volumes of Grendel brass, 7.62x39 neck sized and 7.62x39 fire formed at one time but I can't seem to find the data. If I have time this weekend I'll see if I can do it again.

[Fat Albert]

Ran QL and McGowen Precisioon's twist rate calculator and it worked out with a 16" 1/8" Grendel barrel, 160gr Hor @ 2.260 oal and 6.64gr Trailboss (70% min load)= 1017fps - BUT- your bullet holes will be 1.243" long and 0.264 wide. With I/8" you need 1800fps to stabilize that bullet. You would need 1/6" or FASTER at 1017fps.

[Ammon]

This post was made before I read the posts above me. I was unaware of Secondary Explosive Effect at the time of my post. Upon researching I would highly recommend you not follow my methods below, or do so with a proper understanding of possible risks.

Hopefully my experience today will lend some good ideas.

I was testing homebrew subsonic loads for my 300bo using 123gr b-tip, when usually people say you need to approach 200gr bullets for success.

I reduced my powder load to 10 grains and of course had cycling failures. I took apart my buffer, removed the 3 weights, put it back together and in the tube, and viola!

Normal .750 port, normal bcg, no suppressor, 8.25" barrel.

Essentially, try the same with grendel. Reduce the buffer weight so a reduced powder/pressure load will have sufficient oomph to push the buffer back and chamber the next round.

[Klem]

Ammon,

Very interesting...What speed were those 123gn b-tips coming out at? Did you try it with one weight?

Sounds like you have converted your 300BLK into a 9mm equivalent.