Okay, let me straighten out something about .300 Whisper

[Pyrex]

I'm looking to build my first .300 here soon. I'm going to be building a midlength AR-15 in .300 whisper or fireball.

One of the things that I'm still a little confused about is forming the cases. Now, I understand you can buy a die set when essentially does forms the case. However, it seems SSK recommends to form from .221 - which for me doesn't make much sense - because the whole appeal of the cartridge is the cheapness - I can use .223 cases and .308 surplus projectiles - best of both worlds. I just want to straighten out that I CAN use .223 brass to form the .300 cases?

Also, as far as gas blocks, everyone recommends an adjustible gas block for the large and smaller projectiles and pressures. If I were to just install a basic gas block on a 16" .300 whisper barrel with a pistol gas block location, I would presume it would probably be best for subsonic rounds - would that be right? What's a reasonable but effective adjustable block you might recommend?

Thanks for everyone's time, I really appreciate it.

[Titleiiredneck]

Originally Posted by Pyrex

I'm looking to build my first .300 here soon. I'm going to be building a midlength AR-15 in .300 whisper or fireball.

One of the things that I'm still a little confused about is forming the cases. Now, I understand you can buy a die set when essentially does forms the case. However, it seems SSK recommends to form from .221 - which for me doesn't make much sense - because the whole appeal of the cartridge is the cheapness - I can use .223 cases and .308 surplus projectiles - best of both worlds. I just want to straighten out that I CAN use .223 brass to form the .300 cases?

Also, as far as gas blocks, everyone recommends an adjustible gas block for the large and smaller projectiles and pressures. If I were to just install a basic gas block on a 16" .300 whisper barrel with a pistol gas block location, I would presume it would probably be best for subsonic rounds - would that be right? What's a reasonable but effective adjustable block you might recommend?

Thanks for everyone's time, I really appreciate it.

paladin's gas block, TP555 on here, you can buy brass from hoser on here cheap also. The chamber will work with 223 but I wouldnt reccomend a ssk upper since you can get the same quality for cheaper on here from spook or tp555 or other vendors on the net. You should b ok with super and subs with a pistol position 16" upper but you may have to play with handloads some to find the right combo.

If I were doing this over then this is personally what I would do.

Side charging upper/carrier "mega machine upper the bcg they reccomend also"
yhm ff tube "works with tp555's block if i am correct"
spooks barrel threaded 5/8x24 tpi
magpul 20 round mags.
heavy buffer

upper should run around $550 minus the barrel and block since their prices to machine are dependent on material cost at that time. You can also get a 300 blackout barrel and use the same brass/data as the whisper.

The reason I say the side charging upper is that you can cut the gas off and use it simmilar to a bolt action which is the cats ass when suppressed fyi.


Just my personal opinion and 2 cents free of charge

[snipecatcher]

Originally Posted by Titleiiredneck

yhm ff tube "works with tp555's block if i am correct"

It works, but will require some minor cutting. Nothing a dremel/file can't handle. I will second the side charging upper. I wish I would have gone that route, and will on my next one.
-Dan

[srm109]

I'm using a "300 Fireball" barrel from Model 1 Sales with the gas port in the carbine position. I use 223's cut down with a sanding disk on my old ShopSmith. I then reform them to make cases with a Redding die set. I use a neck reaming bit in my old Pacific trimmer with a Forster inside neck reamer to ream the inside of the necks and trim the length of the cases at the same time. Takes me about 2 hours to make 100 cases. The inside neck reaming is probably not necessary, but doesn't cost me any time since I trim and ream at the same time.

I haven't had any major problems with subsonic or supersonic loads. As long as the bullets are heavy (210+) it shoots subsonic. The lighter bullets (125, 150, 175's) perform well as supersonic loads. I guess the extra pressure that builds behind the heavy bullets seems to work the action well.

I'm using a cheap collapsable stock and carbine buffer that I got from Cheaper Than Dirt, a Model 1 Sales barrel and gas block, a DPMS slick-side high-rise upper. I'm shooting 1/2" groups with cheap surplus 147gr FMJ's at 100 yards running about 2300fps. I've run cast lead 200 grain RCBS bullets and gotten 2" groups running about 800fps. Sierra 220's run about 750fps with the same results.

Total cost of whole firearm = $700 not counting the scope!

[rsilvers]

I don't recommend an adjustable gas block. And mid-length will not work at all.

16 inch carbine position is what I went with and what I recommend for general use.

Pistol position is better if you want to experiment with very fast powders, but then you should not shoot full power ammo unless you have an adjustable gas block.

[Hoser]

Using 223 or 5.56 brass is fine for just about all the chambers out there. Some really old SSK chambers are on the tight side with regards to neck thickness.

I have used 221 brass in the past and it works just fine, but is kind of a pain and isnt worth the expense. In fact I still have 200 pcs of virgin brass sitting on the shelf that I made for a member here just like he asked me to. Then stiffed me.

I use all flavors of brass and have had nothing but good results. Everything from Lake City to Lapua. Commercial Federal is my least favorite, but it does work. I run Lake City or mixed brass in my semi (soon to be full) and Lapua in my bolt gun.

I am using a PRI adjustable gas block on my 9.0 Noveske. I dont shoot supersonics, but being able to is a nice option.

For gunsmithing/building, get in touch with Spook who is a member here.

[alorton]

Originally Posted by Titleiiredneck

paladin's gas block, TP555 on here, you can buy brass from hoser on here cheap also. The chamber will work with 223 but I wouldnt reccomend a ssk upper since you can get the same quality for cheaper on here from spook or tp555 or other vendors on the net. You should b ok with super and subs with a pistol position 16" upper but you may have to play with handloads some to find the right combo.

If I were doing this over then this is personally what I would do.

Side charging upper/carrier "mega machine upper the bcg they reccomend also"
yhm ff tube "works with tp555's block if i am correct"
spooks barrel threaded 5/8x24 tpi
magpul 20 round mags.
heavy buffer

upper should run around $550 minus the barrel and block since their prices to machine are dependent on material cost at that time. You can also get a 300 blackout barrel and use the same brass/data as the whisper.

The reason I say the side charging upper is that you can cut the gas off and use it simmilar to a bolt action which is the cats ass when suppressed fyi.


Just my personal opinion and 2 cents free of charge

Funny you mention those build points. Mine is almost what you speak of. I have a 10.5" Noveske barrel, ASA side charge upper, pistol gas system, TP555 3 way gas block (hi/low/off), a YHM free float tube, and a YHM 7.62 suppressor. I switch the gas block to full open for subs, restricted for supers, and off if I want to be as quiet as possible. The non-reciprocating ASA side charger means I can use my support hand to work the action with the gas turned off and never remove my firing hand provided I'm on a rest or bi-pod. It's a great setup and I have fun with it.

BTW, my TP555 gas block didn't require any filing to get under the YHM free float tube. I'm using the mid-length customizable version. I did drill out a hole over the adjustment point on the gas block to make switching gas settings easier.

[mstarling]

I found that the YHM Light Rail slots line up to allow access to the Paladin (tp555) gas block in the pistol position with no modifications at all.

[Pyrex]

I'm resurrecting my own thread here - so everyone back off! :)

I appreciate all the great info. I'm primarily interested in barrels and gas blocks, not complete uppers - I plan on building this upper. What is a good resource for reasonably priced .300 barrels? I know Green Mountain at one time made some barrels (probably for another vendor) but usually they don't thread their barrels.

I haven't made my mind up if I'm going to build a .300 in 10.5" and SBR, or 16" and keep my $200 for the suppressor. One thing I'm still unclear on is the gas block location. From what I would presume - having a pistol located gas block would allow me to squeeze ever bit of pressure out of subsonic loads, but I would need an adjustable block for supersonic rounds (which I definitely will want to fire hog hunting). Is there any disadvantage to a pistol length gas block? One question I'm having trouble with is what kind of hand guards am I limited to with a pistol located gas block? I'm assuming a large free float would probably work regardless?

Lastly - I'm sure this question gets asked all the time (I combed the forum trying to find it) - What the hell is the difference between all these .300 variations? .300 Whisper, .300 fireball, and now we have .300 blackout? I'm assuming it's just a name rights issue, but do these actually have any differences? My concern primarily revolves around being able to find dies to reload and case form.

I really appreciate any help you guys can lend.

[mstarling]

rsilvers takes the position that a carbine length gas system can be used for both subs and supers . What he doesn't tell you is that while this is true ... it is true for a very, very small selection of powders ... like AA1680.

The down side of a pistol length gas system with a three position gas block is that it is not safe to shoot a supersonic round with the gas system set on the subsonic position.

So ... take your choice ... lots of flexibility with loads but very good function with the three position gas block at the price of being VERY careful not to screw up versus limited flexibility in powder choice with the carbine position gas system.


I personally have a Paladin barrel and pistol length 3 position gas system. Was bought before the 300 BLK was introduced ... but I would still choose to do it that way because it works VERY well.