Model 1 Sales 300 whisper upper function problems

[mtb8r3]

Hello all.

Sorry I have kept quiet so far, but I lacked anything of substance to say. Just been browsing the site and learning what I could about the Whisper.

Two weeks ago, I recieved my first .300 ar barrel form model 1 sales. The package was shipped from Il to MO for $18. I called, and they said they made a mistake (that was the shipping on a complete upper..????) Anyway, I am waiting on the $8 they are suppose to re-credit.

For anyone wishing to go this rout and build their own, pay attention. Their 300 barrels have a different thread for muzzle devices! No where do they mention this, but your stock AR flash hider will not work. I called up, and they said they would ship one out for an additional $20, plus $7 PHI. These guys relly need to get on board with the USPS.

Anyway, I assembled everything last night, and headed to the range today. As everything else I reload is either mid-level pistol, or high power rifle, I didn't have any magnum pistol powders on hand. I decided to go with H110 due to its versitility, and loaded up some loads. Using info found on line, I fixed up 2 subsonic, and one supersonic load (210g berger, 200g Lapua RN, and 165g Barnes solid.... Hey, its what I had laying around). Thanks to the discussion here, I was not supprised when nothing cycled. The hot 165's would half-extract, but the rest didn't even unlock. Now, granted, I don't have a chrono, and it is below zero outside, so velocities were likely below what they should have been. So I went home.

Got into the gun room here, and started reading over the other threads. I checked my port diameter, and sure enough, just over .1285 (#30 fits). I tried some 200 grain bullets, but jumped the powder from 9.1 to 11gr. Went outside and proceded to make some BIG holes in the earth.... Still not cycling. I dedided to try the non-adjustable gas system off my standard AR carbine....Still not cycling. The bolt will half extract, and stick.

Scratch head....Idea. I looked at the bolt/carrier I was using. While it didn't cycle roughly, it was still just a parkerized finish. I pulled the chrome plated bolt from my other carbine (Matte silver type), and loaded up 3 more rounds. You can appreciate my joy when I watched 3 little pieces of brass jump smartly from my ejection port. Looks like there is hope after all.

Now that things are working, I can begin some real testing. Sorry if I was a bit long winded, by I just wanted to share in the frustration that some of you have experienced. I hope that this was helpfull to at least somebody, and will keep you all posted with future range reports.

[mtb8r3]

Just conducted another test. Looks like 11 g is a bit hot. 10 grains looked good in pressure signs, but only cycled completly about 50% of the time. I think I will look somewhere in between for this bullet (200 gr Gameking). As soon as I get access to a chrono, I will provide addiitonal data.

[Greywuuf]

about the "odd" thread size on the muzzle. I called and asked about that. They do it on pourpose to keep us from hurting ourselves. It is threaded 1/2"x36 tpi which is the same as the 9mm ( and 7.62x39 I think ) that is to keep us from screwing a .223 flash hider on there and trying to shove .308 bullets through it .

look around you might find something you like better that is compatible.

[Zed Stewart]

I guess they do not realize that a standard A1 or A2 hider is plenty big for a .30 caliber bullet. A .308 round will go through up to the shoulder.

[jripper]

I can kind of see their logic on that one. Altough a standard A1 or A2 flash hider may be big enough for a .30 bullet, some of the various .22 muzzle brakes that you could install may not be.

I still wish they would have used the standard AR thread though.

[jripper]

Update:

I think I have this thing figured out. It will run reliably with 220 and 240 graind Sierra's, subonic. Put 20 rounds of 11 gr. AA 1680 and 220 Sierra bullet through last Sunday, and ejection was quite positive. Did not chronograph, but they were very quiet, and almost had to be subsonics. I did chrono the 240s with 10.3 g AA1680, and they were only going 850 fps (they did run, however).

The bolt has broken in, and works a lot smoother.

I am still using a full length stock and buffer tube, and have my JP gas block wide open.

Runs good with all supersonics that I have put through it.

Here is what I have concluded about this gun/round.

Bolt needs to be broke in fully (good tip, Quarterbore)

Gas port needs to be .120 or slightly larger.

Need to use slower powders within the reccomended range for this cartridge, to make it run with subsonics.

I didn't really mind the experimenting, as it has occupied me during the winter.

I still would reccomend the upper, with qualifications concerning what is necessary to make it run.

It is an economical way to get into the cartridge.

If anyone buys one, I would reccomend getting a upper without a bolt, and buying a chrome plated bolt from someplace else, however.

Joel

[300whisper_newbie]

Good to hear Jripper! I've just finished loading up about 100 rounds of 11gr h110 with 220 sierras on top. Hopefully I'll get a chance to run them through my upper this weekend. If they don't eject I'll pick up some AA1680 and see how that works.

Thanks for the info!

--Chris

[mtb8r3]

Let me know how that load works in your gun. As I mentioned eariler, 11g of H110 with a 200 gr Gameking had VERY bad pressure signs. The brass I attempted to reload would not even hold a new primer. I finally settled on 10.2g for reliable operation, though I still need to chrono it.

[300whisper_newbie]

Originally Posted by mtb8r3

Let me know how that load works in your gun. As I mentioned eariler, 11g of H110 with a 200 gr Gameking had VERY bad pressure signs. The brass I attempted to reload would not even hold a new primer. I finally settled on 10.2g for reliable operation, though I still need to chrono it.

Don't tell me that, guess I better watch for pressure signs on my 220s, would hate get a KB so early in the game :( What was your parent case? I was told that using 223 parent cases reduces the internal volume slightly which is why I used the 221 fireball brass. That could explain why you would be getting pressure signs early. I used 10g h110 with 220 SMKs and didn't see any pressure signs at all so far.

--Chris

[jripper]

Just for information, I went up to 12.0 grains W296 with 240s, and pressures were fine. It is very similar to H110. I can't remeber which brass I used. I guess each gun is different, as towards maximum loads.