Id say that is pretty close. Im going to use BTHP's for my 220's, so Ill be interested to see what difference that makes. Longer barrel as well compared to yours. I think I said before Im going to use H110. I also grabbed a pound of IMR4198 to play with.

quote:

Originally posted by StorminNormin:

quote:

Originally posted by TKO:
I snagged some 150gr SMK's a few days back, so Im going to work up a load for them.

That's a pretty serious drop at 50 yards! What were you seeing for velocity on those unsuppressed?

I worked up loads starting at 8.2gn Hodgdon Lil'Gun up to 8.7gn with OAL of 2.120".

8.6gn seemed the most accurate but I saw no signs of pressure at 8.7 so I may go a little higher or just use these suppressed only. I also may adjust the case length a little longer and continue to work with the load to get the velocity closer to 1100fps.

Unsuppressed Velocities:
8.3 - AVG 1030 ES 82
8.4 - AVG 1026 ES 30
8.5 - AVG 1043 ES 22
8.6 - AVG 1061 ES 29
8.7 - AVG 1051 ES 61

Suppressed Velocities:
8.3 - AVG 1050 ES 21
8.4 - AVG 1049 ES 37
8.5 - AVG 1047 ES 65
8.6 - AVG 1068 ES 51
8.7 - AVG 1081 ES 34

OK, so I got in some Remington 300 BLK primed brass and decided to load up some Sierra 220gr OTM to see if it will cycle unsuppressed with factory brass. I did change my OAL to 2.190" and tested Lil' Gun from 8.7gr to 9.4gr and all would not cycle the bolt unsuppressed and functioned fine suppressed. 8.9gr Lil' Gun was the most accurate suppressed, and unsuppressed it was all over the place. I am still experiencing about a 3" bullet drop at 50 yards. Today I could not use the chrono at the range I went to.



I think I am just going to shoot this suppressed only since that is the only way it functions perfectly and I guess I should anyways since it is subsonic.

So I like 8.6gr Lil' Gun @ 2.120" OAL and 8.9gr Lil' Gun @ 2.190" OAL.

I will be interested to try AA1680 on this round since I have a whole 1# of it.

Is that POI only when suppressed?

Ill be interested to hear how the 1680 does as well. In my travels the last couple of weeks Ive picked up some Lil Gun as well as IMR4198.

Its interesting that you just aren't getting enough gas back to cycle.

quote:

Originally posted by TKO:
Is that POI only when suppressed?

Ill be interested to hear how the 1680 does as well. In my travels the last couple of weeks Ive picked up some Lil Gun as well as IMR4198.

Its interesting that you just aren't getting enough gas back to cycle.

Yeah the unsuppressed was all over and the suppressed was tight. Some of the higher powder loads I did the unsuppressed groups got tighter, but the suppressed opened up. 8.7g of Lil' Gun was also tight suppressed but it failed to lock bolt back on last round. I also don't understand why it won't cycle unsuppressed since factory loads will but we will see how AA1680 does since that is what factory 220gr uses and it is supposed to have more gas volume.

Like I say, I think I would only shoot this round suppressed anyways so I am not too concerned but now it has me wanting to figure it out.

Are you running an H2 buffer in the AR?

quote:

Originally posted by TKO:
Are you running an H2 buffer in the AR?

Yes it has an H2 buffer.

That is just bizarre. I wouldn't guess it was under gassed but it must be to work suppressed.

Granted its subsonic it would still be nice to know it functions in the rifle without the can on it.

Im going to start with H110. Once I get a few rounds made Ill send you a few to try.

I grabbed another 2K of the Remington 7.5's over the weekend as well. I found them at Sportsman's so I put the hooks on em. Figure at this point whenever I see something Im going to buy it and pop it on a shelf.

Any new loads Stormin? Curious if you had figured out the cycling issue on the unsuppressed side.

quote:

Originally posted by TKO:
Any new loads Stormin? Curious if you had figured out the cycling issue on the unsuppressed side.

Not yet, I have 2 loads of the Sierra 220gr I want to test to see which works best. They are the different OAL and powder weight of both I felt were accurate to see which one I want to load.

I have been out of town the last week so I have not been able to work up anything. I want to load up the 220gr with AA1680 and see if that will cycle.

I just got in some Hornady 208gr A-Max bullets that I want to work up and try out.

Definitely interested in how the Hornady 208's work. I have quite a few of the SMK 220's but if the results are promising on the 208's Ill switch them out.

I just spent quite a while reading through this thread. I'm on the fence about starting to reload .300BO. Like you said in the early post, there isn't a lot of great load data out there, but this thread is pretty great.

Please keep us posted on your work!

If I can ever get my loader Ill join Stormin in working up some loads!

Audiostar,

Sadly right now just about the only way to even shoot 300 BLK is if you do reload; I haven't seen ammo for it in forever! I have some stockpiled but I use that to compare to my reloads or sight in an optic. I personally think it is a great caliber; you just have to keep in mind that this is a CQB round and not something that will be effective beyond 200-300 yards. I have it for CQB and how well it works with the AAC SDN-762 suppressor.

TKO,

That sucks that you are STILL waiting!!!! I hope you get it soon; it took a good while for my dies from Dillon.

I took vacation yesterday and today to do yard work and also plan to finish working up the 220gr loads with AA1680. If I have time, I will work up some of the Hornady A-Max 208gr rounds.

I really want to get some more of the Barnes 110gr TAC-TX black tip bullets as I hear they are probably the best and most accurate supersonic round but they are the hardest bullet to find!!! I have 500 of them so far.

Once I find my pet load for each round, which I will share on here, I will then move to trying to do some ballistic testing although my tests involve wet phone books unless I sping for the powder to make ballistic gel.

OK, I loaded up some more rounds and did some testing at the range today all with the Sierra 220gr SMK.

First I tested the Sierra 220gr using Hodgdon Lil' Gun powder and 3 different OAL.

• 8.9gr @ 2.190 OAL - top left of target.
  
• 9.0gr @ 2.260 OAL which is what Hodgdon's load data states - top right of target.
  
• 8.6gr @ 2.120 OAL - center of target.
  

Unfortunately the rounds WILL NOT cycle the bolt unsuppressed but function perfectly suppressed. I liked the 8.6gr of Lil' Gun @ 2.120" OAL.



Then I tried some of the Sierra 220gr SMK that I loaded up using A1680 powder.

• 10.8gr @ 2.120 OAL - top left of target. Suppressed rounds were VERY tightly grouped.
  
• 11.0gr @ 2.120 OAL - top right of target. Unsuppressed rounds were very tight.
  
• 11.2gr @ 2.120 OAL - center of target. Groups opened up at this powder load.
  
• 10.7gr @ 2.089 OAL - bottom left of target.
  
• 10.9gr @ 2.089 OAL - bottom right of target. I was shocked by the unsuppressed group; 5 shots through what looked like only 2 holes!
  

All rounds using the A1680 functioned perfectly both suppressed and unsuppressed. I had problems with Lil' Gun cycling the bolt unsuppressed and had zero problems with the A1680.



I used new primed Remington 300 BLK brass for all of these rounds today.

The load I will go with for the Sierra 220gr SMK will be using 10.9gr of A1680 @ 2.089" OAL.

If I am going to shoot suppressed only, then I have the option of loading 8.6gr of Hodgdon Lil' Gun @ 2.120" OAL. I will try and test velocities next time.

I figured I would give a recap of my pet loads so far using the following rifle:

Noveske 10" 300BLK
1/7 twist
H2 Buffer
Pistol length gas system
AAC-762-SDN-6 when suppressed

Sierra 125gr OTM
Primer: CCI400
Powder: 17.2 Hodgdon Lil' Gun
OAL: 2.210"
Case: Lake City once fired converted brass
Crimp: Lee FCD 1/2 light crimp

Nosler 125gr BT
Primer: CCI400
Powder: 17.8 Hodgdon H110
OAL: 2.085"
Case: Lake City once fired converted brass
Crimp: Lee FCD 1/2 light crimp

Sierra 220gr SMK
Used Remington primed 300BLK new brass
Powder: 10.9 A1680
OAL: 2.089"
Crimp: Lee FCD 3/4 Med crimp

Lots of work done today!

So looking at the results Id say that last load works pretty well for the Lil Gun. Good group and less powder. Ill be interested to see what that chrono's out at.

Awesome news on the AA1680. How was it audible wise suppressed?

Realizing that the 220's are going to be your subsonic loads it would be good to have a round that works without the can on it. Figures that is the one powder type I haven't been able to lay my hands on.

Just out of curiosity, any idea what primer got used on the Remington brass? Wondering if those are 7.5's by chance and that may be one of the differences...

I got an email from Dillon today. Loader should be here Monday! I have my dies in hand and plenty of components. Still waiting on my .45 dies but that's ok. I have plenty of .45 for the time being.

I gotta get my hands on a chronograph now. Since Im going to start making hunting rounds for the .300 (for varmint) so it will be a good investment.


If you want to go the gelatin route, let me know and Ill share the cost of the powder with you.

quote:

Originally posted by TKO:
Lots of work done today!

So looking at the results Id say that last load works pretty well for the Lil Gun. Good group and less powder. Ill be interested to see what that chrono's out at.

Awesome news on the AA1680. How was it audible wise suppressed?

Realizing that the 220's are going to be your subsonic loads it would be good to have a round that works without the can on it. Figures that is the one powder type I haven't been able to lay my hands on.

Just out of curiosity, any idea what primer got used on the Remington brass? Wondering if those are 7.5's by chance and that may be one of the differences...

I got an email from Dillon today. Loader should be here Monday! I have my dies in hand and plenty of components. Still waiting on my .45 dies but that's ok. I have plenty of .45 for the time being.

I gotta get my hands on a chronograph now. Since Im going to start making hunting rounds for the .300 (for varmint) so it will be a good investment.


If you want to go the gelatin route, let me know and Ill share the cost of the powder with you.

Yes the last load on the Lil' Gun worked good but is suppressed only, which is fine.

I was VERY happy that the A1680 worked well and I figured it would since I heard it has more gas volume compared to Lil' Gun. It sounded VERY quiet since it is the same components of the factory 220gr loads. All I heard was the firing pin drop, very silent shot, and then bullet hit the backstop . I will chrono the one I like with Lil' Gun and also the 2 A1680 that did good. I could not believe on the 10.9gr of A1680 unsuppressed I fit 5 rounds through 2 holes!

I would assume the primer in Remington's primed brass would be their Remington 7.5 primer; I have sent them an email to ask.

EXCELLENT to hear on your loader!!!!!!

I need to look into the gelatine and I have at least one other person willing to go in on a batch so I will let you know.

Now I plan to work on the Hornady 208gr A-Max, but that will be a week or two before I can shoot it. I also need to work up a load for the Barnes 110gr TAC-TX black tip. Once I have several bullets I really like the accuracy on, then I will take them to test shoot at my brother's land with my chrono. It sucks because that is the only place I can do it and it is so damn hot there with no shade when shooting which is why I have only done it once.

I should use some of my airline miles to come make the Pheonix, AZ Sigforum shoot!

If you are serious about coming out you are welcome to stay at my place. I have two guest bedrooms.

Yeah, they probably are 7.5's... If 1680 is the factory ammo powder then you are probably good to go on that.

Understood on the shade part... Its early morning shoot here or nothing for the next couple of months.

I appreciate the offer for a place to stay if I do come; I will let you know once it gets a little closer.

Yup, you can't do anything outdoors after noon now for the next few months.

It has arrived....





Ive got it all adjusted for the initial run except for the powder drop. Wife is glaring at me and I need to go cook dinner...