AMMO TEST #3 ...... results available at last!!

[FJC]

Superficially I would once have agreed about the destabilization .. but having learned the reason for the freebore being generous and why - and adding in close range useage factors ... I think it is something I can accept - personally.  

What is this about the freebore?  I did a search on 'freebore' but it only points to this thread.  Please enlighten me.

[R9SCarry]

Frank ... With a round chambered, there always has to be some gap ahead of bullet ... if it were already engaged in the rifling then pressures would spike dangerously.

In rifles this ''jump'' gap is small .. possibly in order of 0.025" .. it is something reloaders try to get right . just enough - not too much - but certainly not too little or none.  This is why OAL of cartridge is very critical with rifle reloading... for safety and optimum performance.

In handguns it is less critical by comparison but required for same reasons.  A revo doesn't need one ... it has a cylinder throat and gap already and so looses peak pressure safely.  In auto's it is more critical and necessary.  Karl elected with the R9 barrel design to give a large freebore of 0.025" in order to bring the peak pressure level down to a safe region before rifling is engaged - thus spare the whole mechanism from possibly destructive effects of severe pressure spike - safeguarding too I'd say the chamber walls too.

It is this generous freebore which now seems likely to at times permit slightly uneven engagement of rifling as the bullet jumps the gap and then ''bites'' rifling.

Don't know whether this helps any.

[FJC]

Thanks.  I familiar with what freebore is, but hadn't seen anything on it being different in the R9 than in other pistols.

[R9SCarry]

Sorry Frank .. musta sounded like I was trying to teach Grammaw to suck eggs!  Just ran thru the whole deal from habit!

[RJ HEDLEY]

R9SCarry
 Thanks for the lesson,  some know, some don't..

I have wished for years now, that God had put a little gauge,  like a Fuel Gauge, on everyone's forehead.  So you could look and see if that person had a "Full" tank,  or was running on "Empty"....

[R9SCarry]

RJ ... haha .. you too eh?  Yes indeed - how many times did I wish for that lil' gauge ..... sometimes I assume it shows full when it doesn't but more often, I assume empty or part full and plow on ranting away and prosthelitizing ... in all innocense!

Hey .. BTW .... LOVE the new avatar ... very cool Sir!  I think we should all post self pics .. put faces to each other!

[Datan]

R9SCARRY,
Just wanted to add my thanks for your great work.  Insightful, interesting, and well presented!  A lot of work to put together - much appreciated.

We'll have to wait for a while before we try to get you to test even more  .  I, for one, will be happy to send a bunch of ammo for any future testing...

[R9SCarry]

Thank you Brian .. well, perhaps by time I get #2 R9 I'll be ready to put some more ammo thru ... break it in!!  It is rather time consuming but it is also rewarding in as much as we all benefit .. even tho in the theater of testing I am no pro'!!

I think we have covered most ammo brands that matter for now - broken the back of it perhaps.  But daresay down the line we'll have a few more yet.

[Mr_Jody_Hudson]

Excellent Chris... as we have come to expect from you.  You sent a very high standard for yourself - and have once again accomplished it WELL.  Thanks!    

I know that was a LOT of work.  Now, I'm just hoping you didn't Read all those papers, just shot them.    A most perfect use for printed news in most cases!  

Now, how can we do some useful ammo testing with TV news?

Again, thanks!

[Richard S]

Chris:

Your ammunition tests and reports are truly extraordinary pieces of work!  Thank you!

RS

[mjt]

I really appreciated reading this test.  Thank you for all your trouble.  

OK, so I have to ask this question and maybe it is an empirical one and not answerable without actual tests.  But this whole idea of bullet instability makes me wonder what effects that will have on the degree to which the bullet will penetrate and do damage.  A big reason for going with this gun is that is shoots 9mm rounds instead of a .380 or similar caliber from small guns.  But will the instability make the bullet more comparable to a stable but smaller caliber bullet in its effect?  That is, will an unstable 9mm round penetrate and do damage similar to a .380 round that is stable?  Or will that be offset by a larger wound channnel when the bullet is moving off its axis as it moves forward...or what?  Thanks in advance for thoughts!

[R9SCarry]

mjt - welcome to the forum ..  

Re your points ... IMO - broadly speaking - the occasional round which can occuir with a slight deviation from axis as it leaves the gun, is within the short distances envisaged in a combat situation ... still going to do damage - plenty I'd say.

My thinking is .... the sort of tumble which I would anticipate - (when it occurs) - would be in region perhaps of some 5º as an absolute max ... thus, I consider that on impact the HP will still probably try and expand ... if of suitable design .. like Gold Dot - but marginally asymmetrically.  Once expansion has initiated, the bullet ''off axis'' element will almost certainly IMO produce a significant yaw .. and thence rapid tumble effect.

Clothing density will, as ever, affect performance but I do think that penetration will be more than adequate and the damage quotient considerable .. possibly even more at a shallower depth than a ''straight and true'' bullet impact.

This really is why I do not treat the possibility of an occasional tumble effect with any great degree of concern ... consider maybe the old days with a 38spl wad cutter ... it delivered an affective hit and probably quickly gained some tumble too - if meeting varying tissue/bone densities .. and yet - results were  probably considered well adequate.

So - 6+1 - of the right ammo will for me be just fine ... even if one of those were to yaw a bit.  Our aggressor will I am sure not be aware of any great reduction in wounding potential!

[Mr_Jody_Hudson]

And if it some how twists totally sideways.  I guess it will just hit with a big KER....THUMPP.  

Actually, just kidding, I agree with Chris above.

[mjt]

R9SCarry,
Thank you for those thoughts.  Did you observe any differences in penetration depths across the bullets that showed sooting vs. not or were they pretty much the same?  I guess that might be one way to measure the degree to which it makes much difference.

[R9SCarry]

mjt ... All I can say - as a generality really .... is that when doing penetration tests, bullets that showed some tumble and unequal expansion where pretty much ''down there in the pack'' along with symmetrical ones.  So do not think it prejudices penetration all that much ... JMHO.