Gunsmithing .300 Whisper vs .300 AAC Blackout chambers, reamer

[rancilio]

.300 Whisper vs .300 AAC Blackout chambers, reamer

I intend to build a super-silent bolt pistol with a Shilen 16in SS barrel
based on on an XP-100 action. I already have a break-barrel single-shot TC
Encore 16in MGM barrel in .300 Whisper and an M&P .300 Whisper/.300 AAC
Blackout with a JP silent buffer and JP adjustable gas block.

So my questions are, do I chamber the XP in .300 whisper or .300 Blackout?
Will I compromise accuracy yet gain flexibility with a Blackout chamber when
shooting Whisper ammo?

I intend to reload, but just have not gotten there while still active duty
and moving around. I have the chamber specs and have read everything that I
can find but cannot decide. I know that my Encore Whisper is MOA, or as
close as I can tell out to 150y.

Shilen has both reamers by the way, or at least a .30/221 and the Blackout.

Please let me on to your wisdom. Thanks.

 

[BusterB]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

whisper can be shot in blackout, blackout should not be shot in whisper. While you have reamer could be worth just rechambering the whisper you already have to blackout.

 

[rancilio]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BusterB</div><div class="ubbcode-body">whisper can be shot in blackout, blackout should not be shot in whisper. While you have reamer could be worth just rechambering the whisper you already have to blackout.</div></div>

That is what "they" say, but I have read plenty of anecdotals that suggest otherwise. Plus, I see some slight variations to dimensions all labeled .300 Whisper or .300/221 or .30/221 or 30-221. An old spec I saw did not even get to the thousandths place which would make the the whisper and blackout the same.

Will I compromise accuracy with a Blackout chamber when shooting Whisper spec'd brass or ammo?

 

[BusterB]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

I wouldn't imagine it would be significant, however if you already have a reamer it would be pretty easy just to get some consistency across the board, just my opinion. Would also make reloads a little easier to somewhat standardize.

 

[jetmd]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

I would read the article in the American Rifleman about the comparison of the two. The article contains a drawing of each round, chrono testing of loads and some interesting dialog with regards to JD Jones and his developement and also Q&A with AAC in respect to the Blackout round.

It is a well written article. I think it will help answer many of your question.

Regards,

Chet

 

[rancilio]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

Thanks Chet. I read the article and agree it is fairly well written, although I still have chamber spec, compatability and accuracy questions.

 

[rsilvers]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

That drawing they published is just one Whisper(R) drawing. There is more than one. This is why people are told they cannot shoot Blackout in Whisper chambers - because they may have the shorter throat version rather than the one that you saw which looked nearly identical.

Picking one of the earlier designs is much like wanting to chamber in 22 Varminter after the 22-250 was standardized.

 

[softcock]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

I have been told & I believe there is MORE deviation in different .308 Win. Reamers than between the 30-221/whisper & 30 BLK .
<span style="font-size: 11pt"><span style="font-weight: bold">But no debating , ' It is good ' to have a standardized/saami spec. BLK Reamer from now-on for all to be the same with factory ammo .</span></span>

I just used the same PTG 30-221/whisper Reamer that I have always had & just added a touch more Throat to the barrel setback to mimic the BLK on this last boltaction barrel. Don't know if I will ever wear-out this PTG Reamer & get a BLK reamer .

When buying New BLK Brass for your loading . IT does not matter if it's a BLK or 30-221 chamber that new brass is going into .
Shooting AR's, Side X Side exact same barrel & barrel-length . One in 30-221/whisper & one in BLK .
' Using hand loads ' & 110 grn v-max .
The BLK was able to burn another 1/2 grain of N-110 with better looking & not so flattened Primers because of the extra throat it has to relieve the pressure .

I do think I got just a little tighter groups on paper using the PTG 30-221 and the shorter throat when firing the 110's . But in reality it does not matter because I am not shooting bench Match with it . It is shooting tighter than MOA & that's good enough for what I use it for .
.

 

[Hoser]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

For shooting the 300 through a bolt gun, try the 300 Hush reamer made by PTG. It is
essentially a 300 Whisper "Match" reamer.

My 16.5 inch bolt gun shoots bugholes out past 200 yards with 220 Sierras and Vhit N-110.

 

[softcock]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

30-221 in Boltgun I have had a few . Ya if you were going to Handload only . I think for accuracy from the Boltgun I would do the shorter throat from the 30-221 Rem. Reamer . Or the Match Reamer suggested by Hoser .
Starting with you own chamber ream . For the pure accuracy you could give what ever throat you wanted & with what ever bullet you prefer to shoot .

For the 30-BLK . The 110 grn bullets don't seem to really mind the jump & are plenty accurate for what I do . & you can squeeze just a little more Vel. if your going for the speed .
There really is not that much more of added Throat over the 30-221 Rem . But if your going for the pure accuracy with handloads on the Boltgun . Extra 50-k of an inch or so is not much for extra Throat, but Having a little shorter throat would give you a little more bullet in the Neck with Seating .
.

 

[biffj]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

I guess I'm surprised by the opinions here....I chambered all my 300's with a Manson reamer for 30-221 and I have no issues shooting factory blackout ammo either sub or super sonic in my chamber. I measured the bullet seating depth on my 220gr loads vs the factory blackout and found that they are seating their bullets about 20 thousandths deeper than mine. I set my bullets about .015" off the lands so that makes the blackout factory ammo about .035" short. I've always heard that the blackout throat was shorter than the other generics and only the very early 300 Whisper had a short throat and tight neck. Maybe I just got a good reamer setup which allows the use of pretty much any of the ammo loaded for all of them. My bolt guns all got sold before I had a chance to do much with them but my semi auto SIG 552-300 seems to be pretty accurate with a 9" barrel.

Frank

 

[rsilvers]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

You have a Sig 552 in 300 BLK?

I see:

http://www.quarterbore.net/forums/showthread.php?t=1835

 

[rsilvers]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: biffj</div><div class="ubbcode-body">I guess I'm surprised by the opinions here....I chambered all my 300's with a Manson reamer for 30-221 and I have no issues shooting factory blackout ammo either sub or super sonic in my chamber.</div></div>

It is not that 300 BLK won't "work" in certain other chambers. It is just that pressures will go up if the other chambers are shorter in throat or tighter.

 

[softcock]

Re: .300 Whisper vs .300 AAC Blackout chambers, reamer

That Sig.552 folder is a Real Sweet Cal. conversion . I am a little jealous of owner of that one .

ALSO : Quarterbore is back up . !!! . NICE .
was good surprised. ( I logged-in ) & it all looks current & up to date when I opened-up the link to the Sig.
.