Subsonic 175s over Red Dot for 10.5" pistol gas?

[jasonusvi]

I plan to shoot my Noveske 10.5" 1x8 300 Fireball with pistol gas system for the first time this weekend. My goal is to keep the variety and cost of components down and so want to use 175s that I use in my 308 and powder I can use in my 45acp.

I have seen a few loads starting with 175 over 6 of red dot. Anyone have experience with this particular load or a similarly compatible load?

Had this barrel made LMT MRP compatible so can swap it with my other barrels in a few minutes time. Standard 556 bolt and mags made it an easy decision. Not to mention cheap brass vs. pretty much anything else out there.

Thanks

http://i752.photobucket.com/albums/xx166/jasonusvi/LMT%20MRP/mrpfb5.jpg

[snipecatcher]

I tried Red Dot in my Savage bolt gun with 240 SMK's. I don't remember the exact numbers, but 1 grain of powder was the difference between 600 fps unstable at 100 yards, and a blown out primer, WAY too hot round. I believe I was around 5 grains. I also tried it with 155 SMK's and it worked, but left the bore very dirty. I'll stick with VVN-110. There's no way Red Dot is going to cycle an AR15.

[Hoser]

Red Dot is a little on the fast side of things...

[jasonusvi]

Thanks for the input. Any 45acp powder that also works well for subsonic Whisper?

[jasonusvi]

... There's no way Red Dot is going to cycle an AR15.

I will try an SA carrier and swap my H to standard buffer. Will chrono and hope to find something that the combo will cycle just below supersonic. You may be correct but will report back.

[Fritzcat]

Blue Dot 6.5gr with 175 BT cycles my AR and shows to work with 45 ACP jacket bullets.

[sharky47]

I have been having lots of success with 2400 powder with all sorts of bullets.

That is a GOOD looking weapon by the way!

[jasonusvi]

I will try an SA carrier and swap my H to standard buffer. Will chrono and hope to find something that the combo will cycle just below supersonic. You may be correct but will report back.

Tried my 300FB/BLK today for the first time. Loved it! I tried 6.05-6.1 grains of Red Dot under 175s. Very quiet without and with Nexus III 45 pistol can. It would not cycle despite SA carrier and standard carbine buffer. The chrono results were as follows:

1074 - first shot with Noveske 10.5" FB barrel
1075
1079 - with pistol can
1067 - with pistol can
1099 - with pistol can
1056 - with pistol can

Might a buffer lighter than standard carbine buffer work? It was so quiet that id like to stay with this fast powder if I can get it to cycle. Thanks for the blue dot suggestion... is 6.5 grains under 175s subsonic for you? What barrel length do you use?

http://i752.photobucket.com/albums/xx166/jasonusvi/LMT%20MRP/30s1.jpg

[jasonusvi]

Just took all the weights out of a carbine buffer and will see if the same load will cycle one last time.

[N310toN170]

I would second the idea of BlueDot or VV 3N37, IMR 800x.

RedDot is highly volatile and really dirty. I've had rounds go from sub, working well to dangerously high pressure because of +/- 20* outside temperature and more than a couple times stick the carrier assembly.

[320pf]

In an AR, the fastest powder that will work in the AR platform has a burn rate in the 2400-AA#9 range. LilGun and N110 also will work well in sub-sonics.

You can find more information on the optimum powders for sub-sonic loads... Unfortunately, you will have to read through the post under the 300 Whisper reloading heading on this site to find all the the information.

320pf

[jasonusvi]

In an AR, the fastest powder that will work in the AR platform has a burn rate in the 2400-AA#9 range. LilGun and N110 also will work well in sub-sonics.

You can find more information on the optimum powders for sub-sonic loads... Unfortunately, you will have to read through the post under the 300 Whisper reloading heading on this site to find all the the information.

320pf

Thanks for the guidance. So there is no hope for red dot even with all the weight taken out of the buffer? Ill shoot the 20 i made up and let you know... then try another powder.

[jasonusvi]

Thanks for the guidance. So there is no hope for red dot even with all the weight taken out of the buffer? Ill shoot the 20 i made up and let you know... then try another powder.

It ejected most but would not pick up the next round. Picked up a pound of AA#9 and am loading up a batch with 7.7 grains for the 175s.

Do you guys run FA or SA carriers? Standard or heavier buffers? The new 300BLK comes with an FA carrier and H2 buffer (which I am somewhat surprised about).

[jasonusvi]

It ejected most but would not pick up the next round. Picked up a pound of AA#9 and am loading up a batch with 7.7 grains for the 175s.

Do you guys run FA or SA carriers? Standard or heavier buffers? The new 300BLK comes with an FA carrier and H2 buffer (which I am somewhat surprised about).

The batch with 7.7 grains of AA#9 under my 175s and standard buffer cycled well this morning. I might bump it up a bit they chronoed around 950s-960s and was not happy with the 5 shot group at 100 yards. Following the 300BLK load testing today I swapped to my 18" SS, FA BCG, and H buffer and put another 70 rounds down range. I still can't get over the versatility of MRP.