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7/8/2022 4:49:43 PM EDT
Using this combo for 300 blackout pistol. What load length would be good to start with?
7/8/2022 10:06:34 PM EDT
[#1]
When loading the heavy long bullets in 300 blk, use 2.250. Just a hair under mag length.
7/8/2022 10:12:34 PM EDT
[#2]
Quote History
Quoted:
When loading the heavy long bullets in 300 blk, use 2.250. Just a hair under mag length.
View Quote
I was considering this. Is this to help with reliable cycling? The sub X bullets aren't as long as some at 1.3"
7/8/2022 10:30:17 PM EDT
[#3]
Quote History
Quoted:
When loading the heavy long bullets in 300 blk, use 2.250. Just a hair under mag length.
View Quote

theyre flat points and have a cannelure, if you load them at 2.250 it wont be where the cannelure is. i only shoot mag fed 300blk so i crimp. OP keep this in mind (as well as the CBTO at that COAL).

the latest hornady manual says to load them at 2.070"; i load them at 2.060-2.065".
7/8/2022 10:53:18 PM EDT
[#4]
Quote History
Quoted:

theyre flat points and have a cannelure, if you load them at 2.250 it wont be where the cannelure is. i only shoot mag fed 300blk so i crimp. OP keep this in mind (as well as the CBTO at that COAL).

the latest hornady manual says to load them at 2.070"; i load them at 2.060-2.065".
View Quote
I'm anticipating cycling issues with the N110 maybe? So I could either load at 2.24/2.25ish with more powder or load 2.06/2.07ish with less powder, but I'm not sure about function at that length. Maybe I'm worrying about that for no reason.
7/9/2022 3:00:09 AM EDT
[#5]
Quote History
Quoted:

theyre flat points and have a cannelure, if you load them at 2.250 it wont be where the cannelure is. i only shoot mag fed 300blk so i crimp. OP keep this in mind (as well as the CBTO at that COAL).

the latest hornady manual says to load them at 2.070"; i load them at 2.060-2.065".
View Quote
Go with the Hornady length, because the data is available.

You don't need a cannelure to crimp if you use a Lee FCD.
7/9/2022 10:27:19 AM EDT
[#6]
Playing around with GRT, I think I'm going to use 2.09. At 9.5 gr, that gets me close to 1040 fps. At 10 gr, it's about 1098 fps.  

I figure if 9.5 gr is pretty close to 1040 fps, I can reduce load length by .030 to see what accuracy is like and still be around 1060 fps.

Trying to use as little powder as possible to see just how quiet I can get it.
Function >noise though.
7/9/2022 7:12:09 PM EDT
[#7]
Quote History
Quoted:
I'm anticipating cycling issues with the N110 maybe? So I could either load at 2.24/2.25ish with more powder or load 2.06/2.07ish with less powder, but I'm not sure about function at that length. Maybe I'm worrying about that for no reason.
View Quote

The only way to find out is to load a few up and shoot them. Hopefully you're using a can to help with cycling (im going to assume yes).

I've shot as low as 545 fps when I loaded up my first subs out of my 6.25" (my math was way off). The rifle still cycled fine, but did not lock the bolt back. It was like shooting a 22.
7/10/2022 1:35:57 PM EDT
[#8]
Quote History
Quoted:

The only way to find out is to load a few up and shoot them. Hopefully you're using a can to help with cycling (im going to assume yes).

I've shot as low as 545 fps when I loaded up my first subs out of my 6.25" (my math was way off). The rifle still cycled fine, but did not lock the bolt back. It was like shooting a 22.
View Quote
With N110?

I've used CFE BLACK and that'll cycle anything. It's also dirty and loud as shit.

That was another question I had was how low can you go
7/11/2022 10:55:37 AM EDT
[#9]
Quoted:
Using this combo for 300 blackout pistol. What load length would be good to start with?
View Quote


I never finished load development with them, I had just started when my suppressor got out of jail.  Then I had to buy a new barrel because my PSA

upper's barrel did not have the threads cut right, huge misalignment on suppressor.   Never went back to sub-x when I got new faxon barrel.

I had a box of factory rounds, they averaged 2.07 OAL so that was where I started, bad accuracy.  I was up to 2.1 OAL using IMR4227 and

accuracy was improving significantly.  That is where I stopped developing a load for the sub-x, and at that time a cold bore shot was hitting 1/2"+

higher than subsequent shots at 55 yards.  

I have hundreds of noslers 220 BT and was only ever able to get 100 of the sub-x's.  Made the noslers work so never

returned to the sub-x's I have left.  By the way, OAL varies a fair amount, the ogive on the sub-x's I have was inconsistent by well over +/- 5/1000.
7/11/2022 1:01:40 PM EDT
[#10]
You will not cycle an AR with N110 unless you have a massive gas port. Especially not with 190s.

I had to get 220s up past 1300 FPS to reliably cycle with a carbine buffer and lightweight spring. That's with an 8.3"  Seekins barrel.

Use N120. That will cycle down to about 750 FPS. Maybe lower.
7/11/2022 2:02:53 PM EDT
[#11]
Quote History
Quoted:
You will not cycle an AR with N110 unless you have a massive gas port. Especially not with 190s.

I had to get 220s up past 1300 FPS to reliably cycle with a carbine buffer and lightweight spring. That's with an 8.3"  Seekins barrel.

Use N120. That will cycle down to about 750 FPS. Maybe lower.
View Quote
I have both N110 and N120. Going to try the N110, I read a lot of good information on 300blktalk.com about making N110 and even N105 cycle. Only shit about it is I couldn't find a starting load length. My guess is I'll have to load almost to mag length for it to cycle.

I plan on trying N120 also.
7/11/2022 2:05:07 PM EDT
[#12]
Quote History
Quoted:


I never finished load development with them, I had just started when my suppressor got out of jail.  Then I had to buy a new barrel because my PSA

upper's barrel did not have the threads cut right, huge misalignment on suppressor.   Never went back to sub-x when I got new faxon barrel.

I had a box of factory rounds, they averaged 2.07 OAL so that was where I started, bad accuracy.  I was up to 2.1 OAL using IMR4227 and

accuracy was improving significantly.  That is where I stopped developing a load for the sub-x, and at that time a cold bore shot was hitting 1/2"+

higher than subsequent shots at 55 yards.  

I have hundreds of noslers 220 BT and was only ever able to get 100 of the sub-x's.  Made the noslers work so never

returned to the sub-x's I have left.  By the way, OAL varies a fair amount, the ogive on the sub-x's I have was inconsistent by well over +/- 5/1000.
View Quote
I found good accuracy with H4198 at 2.09. I tried 2.11, but groups went to shit. Ogive numbers have been slightly inconsistent, but not that bad. Thank you for sharing the information.
7/11/2022 2:27:37 PM EDT
[#13]
Quote History
Quoted:
You will not cycle an AR with N110 unless you have a massive gas port. Especially not with 190s.

I had to get 220s up past 1300 FPS to reliably cycle with a carbine buffer and lightweight spring. That's with an 8.3"  Seekins barrel.

Use N120. That will cycle down to about 750 FPS. Maybe lower.
View Quote


Mine cycles fine with nosler 220 BT's and N110 at 1035-1045 fps .  9" faxon 5r gunner profile barrel and JP click adjustable gas block just one click down from full open.

I have a polished buffer spring that is slightly less than a standard spring, but not much.  Mine is not a carbine buffer tube, I have a rifle buffer tube, 3 oz buffer.  It cycles fully without the suppressor on it.
7/11/2022 2:31:43 PM EDT
[#14]
Quote History
Quoted:


Mine cycles fine with nosler 220 BT's and N110 at 1035-1045 fps .  9" faxon 5r gunner profile barrel and JP click adjustable gas block just one click down from full open.

I have a polished buffer spring that is slightly less than a standard spring, but not much.  Mine is not a carbine buffer tube, I have a rifle buffer tube, 3 oz buffer.  It cycles fully without the suppressor on it.
View Quote


Do you know the size of your gas port? And charge weight?

Not sure what my Seekins is, but even at 1250 FPS, JP SCS with three steel weights, and the lightest spring they make for it, and it still wouldn't cycle. And it wasn't even close. Charge weight was 9.5gr. That's even Suppressed.
7/11/2022 2:50:38 PM EDT
[#15]
Quote History
Quoted:


Do you know the size of your gas port? And charge weight?

Not sure what my Seekins is, but even at 1250 FPS, JP SCS with three steel weights, and the lightest spring they make for it, and it still wouldn't cycle. And it wasn't even close. Charge weight was 9.5gr. That's even Suppressed.
View Quote
What was your seating depth?
7/11/2022 3:40:39 PM EDT
[#16]
Quote History
Quoted:
What was your seating depth?
View Quote


2.220". I seat all my bullets 20-50 mils off the lands. I don't get hung up on OAL as a rule. Some of mine are under SAAMI minimums (particularly poly coated lead 9mm), and everything is good for my firearms. YMMV.

To be clear, those were not 190 Subs. These were 220, either Berrys or Everglades. I use both.
7/11/2022 4:12:20 PM EDT
[#17]
Quote History
Quoted:


Do you know the size of your gas port? And charge weight?

View Quote


I have no idea what size Faxon uses for their gas ports, it seemed to be same size as PSA used on their barrel.

Nosler 220 Ballistic Tip.
New starline brass(it has lower case capacity than most), 8.4 gr N110, 2.065 OAL, very light crimp with Lee FCD (factory crimp die)

forgot to mention.  I have loaded some once fired starline brass.  If I don't anneal it first, it creates enough extra pressure to damage the nosler BT.

I could feel it when seating, I seat with a lee hand tool for feel, sure enough it damaged the bullet. When annealed, once fired is fine.

one more edit:

I use RCBS blackout dies, the seater that came with it cannot load a Nosler BT without damaging it.  I called them and they had never had a

Nosler 220 BT, they sent me a new plug for the seater that would allow the BT to get deeper in the plug and contact further down the bullet.  It

works but is not ideal, they told me I could send them a few bullets and they would make one for it specifically.  

I was amazed they sent me a plug free, and said they would make me one free if I needed it.
7/16/2022 8:23:32 PM EDT
[#18]
Tested N110 just a minute ago. I love this powder. Definitely more quiet and way cleaner. Velocities as follows:

10 gr - 1111
9.5 gr - 1073
9 gr - 1028, 1023
8.5 gr - 996, 980


All functioned and BHO. Going to test between 8.5 gr and 9.5 gr. I have a hunch I'll be 9 gr +- .1 gr. Accuracy at 10 yards was a ragged hole, going to see about 50 yards next time.



7/16/2022 8:38:47 PM EDT
[#19]
Quote History
Quoted:
Tested N110 just a minute ago. I love this powder. Definitely more quiet and way cleaner. Velocities as follows:

10 gr - 1111
9.5 gr - 1073
9 gr - 1028, 1023
8.5 gr - 996, 980


All functioned and BHO. Going to test between 8.5 gr and 9.5 gr. I have a hunch I'll be 9 gr +- .1 gr. Accuracy at 10 yards was a ragged hole, going to see about 50 yards next time.

View Quote


Very interesting results.

Which barrel, exactly, are you running?
7/16/2022 9:42:59 PM EDT
[#20]
Quote History
Quoted:


Very interesting results.

Which barrel, exactly, are you running?
View Quote
V seven 6.5" barrel. From what I understand, they use a gas system that is slightly shorter than pistol length and I think their gas port size is .105. Don't quote me on it though.

I was kind of shocked that they functioned as is. Makes me want to grab some N105 just to try it.
7/16/2022 9:56:34 PM EDT
[#21]
Quote History
Quoted:
V seven 6.5" barrel. From what I understand, they use a gas system that is slightly shorter than pistol length and I think their gas port size is .105. Don't quote me on it though.

I was kind of shocked that they functioned as is. Makes me want to grab some N105 just to try it.
View Quote


Grab it quick. It was discontinued.
7/16/2022 10:11:41 PM EDT
[#22]
Quote History
Quoted:


Grab it quick. It was discontinued.
View Quote
Man, I know. And powder valley just had it in stock last weekend.
7/17/2022 9:40:15 PM EDT
[#23]
I currently use 190 subx with N120, 10.4 grains of powder and COAL is 2.075, shooting an AR pistol with 8.5" ballistic advantage barrel.

I bought some N110 to load the 190 subx and 125 TGK, will start working some loads tomorrow to see how the N110 performs.


ETA: 8.1 grains of N110 perform almost exactly the same as 10.4 grains of N120 out of my pistol, everything else stayed the same.
7/22/2022 8:57:25 PM EDT
[#24]


I'll post some data when I get it.
7/22/2022 9:01:55 PM EDT
[#25]
Quote History
Quoted:
I currently use 190 subx with N120, 10.4 grains of powder and COAL is 2.075, shooting an AR pistol with 8.5" ballistic advantage barrel.

I bought some N110 to load the 190 subx and 125 TGK, will start working some loads tomorrow to see how the N110 performs.


ETA: 8.1 grains of N110 perform almost exactly the same as 10.4 grains of N120 out of my pistol, everything else stayed the same.
View Quote


Guess my gas port is rediculously small. Even at 1200 FPS I couldn't get it to cycle. Even with a carbine buffer and reduced power spring.

N120 cycles down to below 800 FPS in the same exact rifle.

Joke's on me I guess.
7/22/2022 10:39:31 PM EDT
[#26]
Quote History
Quoted:


Guess my gas port is rediculously small. Even at 1200 FPS I couldn't get it to cycle. Even with a carbine buffer and reduced power spring.

N120 cycles down to below 800 FPS in the same exact rifle.

Joke's on me I guess.
View Quote

I have a seekins adjustable gas block but it is all the way open so basically the port on the barrel must be thr right size that it cycles at 1000 fps with either powder and throws the brass at 3 o'clock.
7/24/2022 4:22:26 PM EDT
[#27]
N110 velocity ladder:

8 gr - 879
8.2 gr - 930
8.4 gr - 950
8.6 gr - 990
8.8 gr - 1003
9 gr - 1026
9.2 gr - 1035
9.4 gr - 1072
9.6 gr - 1066

I think the obvious nodes are 8.7gr and 9.1 gr. May be a node at 9.5, but the velocity is a little high for me. What you guys think?



Shot at 50 yards.
7/24/2022 5:01:10 PM EDT
[#28]
Quote History
Quoted:
N110 velocity ladder:

8 gr - 879
8.2 gr - 930
8.4 gr - 950
8.6 gr - 990
8.8 gr - 1003
9 gr - 1026
9.2 gr - 1035
9.4 gr - 1072
9.6 gr - 1066

I think the obvious nodes are 8.7gr and 9.1 gr. May be a node at 9.5, but the velocity is a little high for me. What you guys think?

https://i.postimg.cc/k5YCJdfP/IMG-20220723-193636051-HDR.jpg

Shot at 50 yards.
View Quote


What was shot count and ES on the 9.5 load?

How many rounds between cleaning, and how much grime?

Just consider that grime introduces friction so it may be advisable to keep the load on the higher side. Also helps burn cleaner. That said if you don't have concerns with that I prefer to keep my subs in the 1,000 FPS range personally.

The last batch using N120 I actually went 950.
7/24/2022 6:48:13 PM EDT
[#29]
I try to load mine around 1020 fps as I shoot them in a 8.5" barrel and a 9" barrel which keeps them quiet but moving at a decent speed.
7/24/2022 7:14:51 PM EDT
[#30]
Quote History
Quoted:


What was shot count and ES on the 9.5 load?

How many rounds between cleaning, and how much grime?

Just consider that grime introduces friction so it may be advisable to keep the load on the higher side. Also helps burn cleaner. That said if you don't have concerns with that I prefer to keep my subs in the 1,000 FPS range personally.

The last batch using N120 I actually went 950.
View Quote
One shot per charge weight. Satterlee test.
7/24/2022 7:26:15 PM EDT
[#31]
Quote History
Quoted:
One shot per charge weight. Satterlee test.
View Quote


I don't think one charge per weight is what Scott recommends. Your scale likely isn't accurate enough to give decent velocity nodes with a sample size of 1. I think Scott uses 10 rounds per doesn't he? But even 3 or 5 would be better. A typical powder measure can be +/- 0.1 grains easy.

I'd load a bit more before settling in velocity notes if you're really worried about precision.

If not then it's all kinda moot and just pick something. The paper will never know the difference.
7/24/2022 8:08:57 PM EDT
[#32]
Quote History
Quoted:


I don't think one charge per weight is what Scott recommends. Your scale likely isn't accurate enough to give decent velocity nodes with a sample size of 1. I think Scott uses 10 rounds per doesn't he? But even 3 or 5 would be better. A typical powder measure can be +/- 0.1 grains easy.

I'd load a bit more before settling in velocity notes if you're really worried about precision.

If not then it's all kinda moot and just pick something. The paper will never know the difference.
View Quote
https://youtu.be/WSSaiX7akaQ
28:55

I'm using an FX120i.

Looking at the previous test vs this one, the velocity seems consistent with the charge weight. I know it's pretty minimal.





7/24/2022 8:12:31 PM EDT
[#33]
Quote History
Quoted:
https://youtu.be/WSSaiX7akaQ
28:55

I'm using an FX120i.

Looking at the previous test vs this one, the velocity seems consistent with the charge weight. I know it's pretty minimal.





View Quote


Thanks for the link, I'll check that out.

I always load 5-10 at each weight.

I have the ATV4 w/FX-120i. Makes working up ladders a breeze. Crazy that it's been almost a year since I got it already!
7/27/2022 8:13:04 AM EDT
[#34]
Anyone ever try running the 175 gr. Sub-X subsonic?
7/27/2022 10:07:10 AM EDT
[#35]
Quote History
Quoted:
I currently use 190 subx with N120, 10.4 grains of powder and COAL is 2.075, shooting an AR pistol with 8.5" ballistic advantage barrel.

I bought some N110 to load the 190 subx and 125 TGK, will start working some loads tomorrow to see how the N110 performs.


ETA: 8.1 grains of N110 perform almost exactly the same as 10.4 grains of N120 out of my pistol, everything else stayed the same.
View Quote


I never tried n120, but my experience on blackout pistol's shooting subsonic is anything slower burning than H110/W296, 11FS just becomes dirtier the slower the powder gets, and the amount of unburned powder collecting in the suppressor gets extreme by the time you get as slow as accurate 5744.  IMR-4227 won't even properly expand the neck on subsonic loads, the outside of the neck get's quite sooty shooting it, 5744 forget about it.  Not to mention the faster powders are more quiet with a suppressor on the short pistols.
7/27/2022 10:47:18 AM EDT
[#36]
Quote History
Quoted:
Anyone ever try running the 175 gr. Sub-X subsonic?
View Quote
Thought about it, I bet they'd work fine. Since we're talking about faster burning powders, the 175s might have cycling issues, but experimentation is required.
7/27/2022 10:49:00 AM EDT
[#37]
Quote History
Quoted:


I never tried n120, but my experience on blackout pistol's shooting subsonic is anything slower burning than H110/W296, 11FS just becomes dirtier the slower the powder gets, and the amount of unburned powder collecting in the suppressor gets extreme by the time you get as slow as accurate 5744.  IMR-4227 won't even properly expand the neck on subsonic loads, the outside of the neck get's quite sooty shooting it, 5744 forget about it.  Not to mention the faster powders are more quiet with a suppressor on the short pistols.
View Quote
I've got some N105 rounds loaded up. Running through GRT, those will give me a muzzle pressure of around 6500 psi. N110 gives 7500 psi. And those are quiet.

Cycling might be problematic, but we'll find out.
7/27/2022 11:34:06 PM EDT
[#38]
Following. Keep us posted.
7/30/2022 3:43:59 AM EDT
[#39]
Scored a 8lb’er of N110 today. Look forward to loading up a bunch of different loads
7/30/2022 10:20:46 AM EDT
[#40]
Deviating a bit from the original thread. I managed to find a couple hundred 175 gr. Sub-X. I’m really low on N110, but I have a pound on N120.

I used Viht published starting load for a 185 gr. bullet. Although the OAL they used for their Lapua bullet doesn’t work for the Sub-X. I had to go a bit shorter.

I tested these through three rifles. I have a 10” SSK Contender barrel chambered in .300 Whisper. I’ve had it for close to 20 years now. I also have a 16” Noveske barrel chambered in .300-FB. I also built that one some time before the Blackout chambering was submitted to SAAMI by AAC/Rem. The third is a more recent 10.5” PSA upper.



The Contender functioned flawlessly.  it gave me an average velocity of 950 fps. and groups of 1-1/8” at 50 yds.

The 16” Noveske gave me 884 fps. Groups from just over an inch to just under 2 inches. Although I’m going to blame the shooter (me) for the large group. These also cycled flawlessly and locked the bolt fully back, whether suppressed or unsuppressed. I was shooting a standard rifle buffer & spring.

The PSA upper averaged 952 fps. It failed to load the next round twice, and did not lock the bolt back fully. I only shot this one unsuppressed. Group size was 1-3/8”. Standard carbine buffer & spring. I think I’ll add a suppressor and maybe bump the powder charge up a couple tenths.

7/30/2022 11:14:21 AM EDT
[#41]
Nice work. This thread has me excited to get on the loading bench.

I will be loading some Lehigh 198 CF, 220 ELDX, 220 SMK, and some 195 ELDM I just picked up.
7/30/2022 11:18:00 AM EDT
[#42]
Quote History
Quoted:
Deviating a bit from the original thread. I managed to find a couple hundred 175 gr. Sub-X. I'm really low on N110, but I have a pound on N120.

I used Viht published starting load for a 185 gr. bullet. Although the OAL they used for their Lapua bullet doesn't work for the Sub-X. I had to go a bit shorter.

I tested these through three rifles. I have a 10" SSK Contender barrel chambered in .300 Whisper. I've had it for close to 20 years now. I also have a 16" Noveske barrel chambered in .300-FB. I also built that one some time before the Blackout chambering was submitted to SAAMI by AAC/Rem. The third is a more recent 10.5" PSA upper.

https://i.imgur.com/lh34Rwr.jpg

The Contender functioned flawlessly.  it gave me an average velocity of 950 fps. and groups of 1-1/8" at 50 yds.

The 16" Noveske gave me 884 fps. Groups from just over an inch to just under 2 inches. Although I'm going to blame the shooter (me) for the large group. These also cycled flawlessly and locked the bolt fully back, whether suppressed or unsuppressed. I was shooting a standard rifle buffer & spring.

The PSA upper averaged 952 fps. It failed to load the next round twice, and did not lock the bolt back fully. I only shot this one unsuppressed. Group size was 1-3/8". Standard carbine buffer & spring. I think I'll add a suppressor and maybe bump the powder charge up a couple tenths.

https://www.ar15.com/media/mediaFiles/55694/D1262D3F-C159-4E2C-A7A1-D1B1600EB8B9-2470434.jpg
View Quote
Good information, what OAL did you use?
7/30/2022 11:18:32 AM EDT
[#43]
Quote History
Quoted:
Nice work. This thread has me excited to get on the loading bench.

I will be loading some Lehigh 198 CF, 220 ELDX, 220 SMK, and some 195 ELDM I just picked up.
View Quote
Post results in here
7/30/2022 11:26:34 AM EDT
[#44]
I was rummaging around on Vihta's site and I found a pdf that half way down has the full list of their powders with grain size, volumetric density, burn rate relative to n110 based

on manometric bomb tests, and energy density.

They based the burn rate on N110 being the baseline = 100

https://www.vihtavuori.com/wp-content/uploads/2018/07/Vihtavuori-IP-brochure-2018_ENG_www.pdf


The three powders in this thread:

Burning rate from manometric bomb test in lab

N110 = 100 burning rate   mm      mm           g/l               J/g
Powder Burning rate*) Length Diameter Bulk density Energy content

N105           123              1,1        0,8            730            3950
N110           100              1,1        0,8            800            3700
N120           83                0.8        0.6            860            3700


7/30/2022 12:00:31 PM EDT
[#45]
Quote History
Quoted:
Good information, what OAL did you use?
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
Deviating a bit from the original thread. I managed to find a couple hundred 175 gr. Sub-X. I'm really low on N110, but I have a pound on N120.

I used Viht published starting load for a 185 gr. bullet. Although the OAL they used for their Lapua bullet doesn't work for the Sub-X. I had to go a bit shorter.

I tested these through three rifles. I have a 10" SSK Contender barrel chambered in .300 Whisper. I've had it for close to 20 years now. I also have a 16" Noveske barrel chambered in .300-FB. I also built that one some time before the Blackout chambering was submitted to SAAMI by AAC/Rem. The third is a more recent 10.5" PSA upper.

https://i.imgur.com/lh34Rwr.jpg

The Contender functioned flawlessly.  it gave me an average velocity of 950 fps. and groups of 1-1/8" at 50 yds.

The 16" Noveske gave me 884 fps. Groups from just over an inch to just under 2 inches. Although I'm going to blame the shooter (me) for the large group. These also cycled flawlessly and locked the bolt fully back, whether suppressed or unsuppressed. I was shooting a standard rifle buffer & spring.

The PSA upper averaged 952 fps. It failed to load the next round twice, and did not lock the bolt back fully. I only shot this one unsuppressed. Group size was 1-3/8". Standard carbine buffer & spring. I think I'll add a suppressor and maybe bump the powder charge up a couple tenths.

https://www.ar15.com/media/mediaFiles/55694/D1262D3F-C159-4E2C-A7A1-D1B1600EB8B9-2470434.jpg
Good information, what OAL did you use?

My OAL was 1.990”, which works out pretty close to the .250” ogive method that dryflah sometimes talks about.
7/30/2022 1:39:13 PM EDT
[#46]
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Quoted:
Deviating a bit from the original thread. I managed to find a couple hundred 175 gr. Sub-X. I’m really low on N110, but I have a pound on N120.

I used Viht published starting load for a 185 gr. bullet. Although the OAL they used for their Lapua bullet doesn’t work for the Sub-X. I had to go a bit shorter.

I tested these through three rifles. I have a 10” SSK Contender barrel chambered in .300 Whisper. I’ve had it for close to 20 years now. I also have a 16” Noveske barrel chambered in .300-FB. I also built that one some time before the Blackout chambering was submitted to SAAMI by AAC/Rem. The third is a more recent 10.5” PSA upper.

https://i.imgur.com/lh34Rwr.jpg

The Contender functioned flawlessly.  it gave me an average velocity of 950 fps. and groups of 1-1/8” at 50 yds.

The 16” Noveske gave me 884 fps. Groups from just over an inch to just under 2 inches. Although I’m going to blame the shooter (me) for the large group. These also cycled flawlessly and locked the bolt fully back, whether suppressed or unsuppressed. I was shooting a standard rifle buffer & spring.

The PSA upper averaged 952 fps. It failed to load the next round twice, and did not lock the bolt back fully. I only shot this one unsuppressed. Group size was 1-3/8”. Standard carbine buffer & spring. I think I’ll add a suppressor and maybe bump the powder charge up a couple tenths.

https://www.ar15.com/media/mediaFiles/55694/D1262D3F-C159-4E2C-A7A1-D1B1600EB8B9-2470434.jpg
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So you used 10.2gr?
7/30/2022 1:53:57 PM EDT
[#47]
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Quoted:


So you used 10.2gr?
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Correct.

Just got to the range to try 10.5
7/30/2022 3:26:08 PM EDT
[#48]
Quote History
Quoted:

Correct.

Just got to the range to try 10.5
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Let us know if the PSA with can locks back
7/30/2022 10:19:48 PM EDT
[#49]
Ok - some good info, some strange results.  

Using 10.5 gr. of N120 with the 175 gr. SUB-X bullets unsuppressed, I got a 50-yd. group of 1-3/4".  The chrono was acting very strange for this string.  All five shots read between 293 and 328 fps.  These were not the first rounds I shot over the chrono either.  Everything before gave reasonable/expected results. All hit the paper, and at the same POI as when I was shooting unsuppressed the other day.    I checked and re-set the chrono and the next string seemed more as expected.

Shooting the same load again did lock the bolt back in the 10.5" PSA rifle when shooting suppressed.  Average velocity was 966 fps.  Although I intend to only shoot the subs suppressed only, I'd prefer to have a load that functions the gun completely even without the suppressor.  Unfortunately the can caused a large POI shift and I did not get any hits on the target. Interestingly, shooting my standard supersonic 110 gr. VMAX load at 2100 fps. the POI shift is almost nonexistent.  Odd.  

Back to the 10.5 gr. N120 / 175 SUB-X load - the 16" Noveske averaged 1006 fps. and give the best group at 1.188".  
The Contender averaged 1090 fps. and 1.938".  That barrel has always shot faster than the others.

More chronograph weirdness cropped up at this point. This was when I was playing with my 110 gr. load, validating the POI in the PSA gun.  I finished off the mag, shooting through the Noveske barrel. I was getting readings anywhere from 2350 to just over 2800 fps.  Average of the 5 shots was almost 2700 fps.  This same load gave an average velocity of 2314 fps. last time I shot it over the chrono through this gun.  I highly doubt I was getting 2700 fps. from a 110 gr. 300BLK, even with a longer barrel.  So the chrono is suspect.  But that string of 5-shots produced group of 0.875" at 50 yards.  Go figure.
7/30/2022 10:43:09 PM EDT
[#50]
Did the shots with can through the PSA group well just shifted POI?

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