Underwhelmed by suppressed 300BLK noise levels

[TheDan]

Anyone who thinks that any animal is just going to stand there and let you pick them off like flies isn't being realistic.

I've shot prairie dogs before and their buddy will walk up to them to see why he fell over. I've even missed and had them just stare at the puff of dirt quizzically. Makes for an easy follow up shot

The hard part with prairie dogs is getting in close enough without spooking them. They have really good sight and are constantly scanning the horizon for predators.

I've fired a good number of silenced firearms and have not been impressed with the sound level. At our private range, many of our members use silenced rifles and I haven't seen one yet that I'd feel comfortable firing without hearing protection. In pistols, the best ones change the sound from a BANG to a POP!

That's more or less been my experience as well. I do think suppressors would be useful in annoying the neighbors less

 

[tmd11111]

300 BLK was designed for 8-9" barrels. The case volume is such that that max pressure occurs quickly. By 5" the pressure has dropped to around 6,000psi (subsonic) which is sufficient to rack the bolt back. So with pressure dropping that fast a longer barrel might result in the bullet slowing down. It is established that even in supersonic rounds there is no appreciable gains in velocity or accuracy with a longer barrel.

Ummmm.... not quite. I'm no expert but I have been playing with the .300bo for several years now and have put about 4k rounds through 5 different guns. We'll start with super sonic loads. 110gn A-Maxs loaded with 19.0 grains of H110 will loose about 200fps going from a 16" barrel to an 11" barrel. Subsonic loads are a bit less sensitive. I've found that 208gn loads that clock a little over 1000fps in my 16" barrels only loose about 40fps when shot through my 11" barrel.

Edit: The assumed ideal barrel length of 8-9" for complete burn applies to subsonic loads only.

 

[1slow01Z71]

Theres a lot of misinformation in this thread.

Ive got an 8.2" and 16" noveske 300blk barreled gun. With the exact same load the 16" gains 250fps. To maintain the same speed (hair over 1000fps) requires .2gr more powder in subsonic loads for the 8.2 to keep up with the 16. Even subsonic loads have 4x the powder 22lr does so that scenario has no parallels to 300blk.

300blk ARs still have the port pop which makes the rifles seem fairly loud. This is why Im converting my 8.2 to a sidecharger upper with a selectable gas block and will load subs with some regular pistol powder. Then itll be hollywood quiet. I'll use my 6" for the rare subsonic semiauto plinking.

 

[Vaquero]

I've said it before. I'll say it again.
We all have different experiences.
Go with your gut.

 

[rushthezeppelin]

I'll theorize.
The fast burning magnum pistol powders used in 300bo are likely at peak velocity in a 10" barrel. Hornady probably tested those rounds in a 16" barrel, whick would slow the bullets by friction to sub sonic velocities.

Not true. Even rounds loaded as subsonic rounds will get velocity gains out to I believe 22" or 24" barrels. The powder generally burns up around 9" with the magnum powders but keep in mind you still have a huge pressure differential between the barrel and the outside air and so the bullet continues to gain velocity in the barrel. I think most of the manufacturers load their subsonics just to the bleeding edge on an unsuppressed 16" so add in the velocity gain from the can on a longer barrel and you are doing supersonic. I think most of them are loading with shorter barrels and a suppressor in mind (that's what 300bo excels at).

Everyone says that A1680 is the be all do all for the .300bo but I've found that when it comes to loading 208 and 220 subs RE7 and 4227 are more consistent and cleaner.

The only reason 1680 is so touted (IIRC) is because it's pressure curve (I think it peaks late past where a pistol gas tube is) allows it to cycle an AR with a wide variety of sub weights. There are some people with 9"ers that have gotten as low as 155ish gr to cycle subsonic. Unfortunately this late pressure curve leads to dirtier barrels/actions. I think it's also why 1680 is actually somewhat on the loud side for 300 powders too which I think is what the OP is experiencing, the factories are probably using something on the louder side. From what I've heard 4227 is one of the quieter powders and, as you have noted, much more consistent on ES and all that jazz. I'll know here pretty soon as I've got a lb of it to crack open here soon to load some cast/PCed 230 bullets someone on 300blktalk sent me.

 

[Pawpaw40]

From what I've heard 4227 is one of the quieter powders and, as you have noted, much more consistent on ES and all that jazz. I'll know here pretty soon as I've got a lb of it to crack open here soon to load some cast/PCed 230 bullets someone on 300blktalk sent me.

Can you post the results? I'm about to try casting some 230 gr. 30 cal. for 300 BO, interested in trying 4227. Kinda disappointed in 1680 with SMK. (too expensive)

 

[rushthezeppelin]

Can you post the results? I'm about to try casting some 230 gr. 30 cal. for 300 BO, interested in trying 4227. Kinda disappointed in 1680 with SMK. (too expensive)

Well I loaded up some today but alas I wasn't done in time to make it to the range and setup the chrony.

 

[rushthezeppelin]

Can you post the results? I'm about to try casting some 230 gr. 30 cal. for 300 BO, interested in trying 4227. Kinda disappointed in 1680 with SMK. (too expensive)

Got to try em out today.....heres my post on 300blktalk with mah numbers.

So I finally got out today to check the sub loads I was working up (Lee 230s PCed over IMR4227), just not quite sure I'm interpreting the results properly so I thought I would double check

So I originally loaded up 60 rounds, 9.0-10.5 in .3gr increments, so six lots of 10. Unfortunately I don't have full data for each load as I was getting errors on my chrono but I think I have enough to reach some conclusions and tighten my load up.

Started up at 10.5 and worked my way down. First two loads I did all 10 in one mag and the rest I loaded 5 at a time to get some feedback on BHO.

10.5gr - BHO and had a pretty good kick, no pressure signs
1187
1157
1156
1146
1126
1113

10.2gr - BHO and still decent kick
1139
1139
1139
1115
1102
1115
1122
1108
1105

9.9gr - BHO both times started kicking alot less
1094
1079
1106
1061
1089
1109
1093

9.6gr - Only BHO once
971
947
975
981
1042
914

9.3gr - No BHO, barely enough to cycle
907
974
1004
968
874
872
After 6 of this load I decided to call it quits as upon investigation during a cease fire I was keyholing about half of em at 15yds (I am using a 1/8 twist so wasn't too surprised)

As far as accuracy goes (wasn't really trying for it) but the 9.9gr load seemed the best. Obviously the 9.3gr was all over the place with one of the keyholes a full foot above where I was aiming.

So it looks like my magic 1050-1100 load (and hopefully most accurate load is probably somewhere between 9.7gr and 10.0gr. I was thinking of just loading ten of each in that range at .1gr increments.

 

[txpaulie]

Pardon my ignorance...

What is "BHO"?

p

 

[rushthezeppelin]

Barack Hussein Obama of course. He keeps popping up during load testing

I kid, I kid it means bolt hold open on empty mag.

 

[txpaulie]

Barack Hussein Obama of course. He keeps popping up during load testing

I kid, I kid it means bolt hold open on empty mag.

LOL!

Awesome, I get it now!

Thanks,

p