30 arx

[mongoosesnipe]

Mongoose,

Interesting wetpack results. I do know there's someone on the Blackout forum who casts similar size weight lead and then drills a hollow-point into them using a jig. He is trying to emulate the handgun type projectiles with their overly large hollows - a reasonable idea given subsonic Blackout is pretty much the same dynamic.

I have been thinking that if someone could manufacture a round with a very thin serrated jacket full of powdered lead then that would dump pretty much all the energy on the target. A while back I have used powdered lead shotgun shells, and at other times 12-shot for knocking out hinges of doors during entry. This to minimize overpenetration into the stronghold.

I emailed Cor-Bon with the idea a while ago but did not receive a reply. Probably processed by someone who thought I was a nutter (not far from the truth). As you know Cor-Bon makes the 'Glaser Safety Slug'; an thin-jacketed round with a expander ball at the front and fine lead shot behind it. Designed for aircraft entry and Sky-Marshals. In a 220-230gr 30cal Blackout with either powder or fine shot that would work nicely dumping all the energy on the target with no over-penetration.

I have made an experimental round by melting the lead out of a jacketed bullet and filling it with #12 shot to simulate the glaser design but the bullets the bullets end up very light the soft leaf work pretty well and ther are very cheap vs jacketed

[ricsmall]

I've been out for a few days but I think this .30 cal Grendel has already been done. Check out the .308 arrow from arrow Arms. The only brass for it comes from hornady, dies from hornady, and the factory sells you Grendel mags. It's a bad little number. Oh yeah, the factory bolts are AA marked Grendel bolts. My buddy has one. AFAIK, all brass and dies have to be ordered from arrow arms, or at least that's all we found bout a year ago.

Richard

[Nukes]

...no temp-wound-cavity in flesh... no temp-wound-cavity in its wake. If you haven't hit anything critical in the crush-trail you end up shaking your head at the irresponsibility of wounding an animal in flight.....So it's all up to shot placement and crush trail....

In ELASTIC tissue, e.g., "flesh" and "guts," the temporary wound cavity makes no significant contribution to the terminal effects. The temporary wound cavity only makes a significant contribution in INELASTIC tissues, e.g., brain, bone, liver.

"Shot placement and crush trail (permanent wound channel)" are indeed what are most significant.

As for Glaser Safety Slugs, they make ugly looking superficial wounds. I would never trust the life of anyone I love to such projectiles.

[Klem]

In ELASTIC tissue, e.g., "flesh" and "guts," the temporary wound cavity makes no significant contribution to the terminal effects. The temporary wound cavity only makes a significant contribution in INELASTIC tissues, e.g., brain, bone, liver.

"Shot placement and crush trail (permanent wound channel)" are indeed what are most significant.

As for Glaser Safety Slugs, they make ugly looking superficial wounds. I would never trust the life of anyone I love to such projectiles.

I respectfully disagree with all your thoughts.

[457ciSBC]

I've been out for a few days but I think this .30 cal Grendel has already been done. Check out the .308 arrow from arrow Arms. The only brass for it comes from hornady, dies from hornady, and the factory sells you Grendel mags. It's a bad little number. Oh yeah, the factory bolts are AA marked Grendel bolts. My buddy has one. AFAIK, all brass and dies have to be ordered from arrow arms, or at least that's all we found bout a year ago.

Richard

Correct, nothing new to see here. A few short range 100-300yd BR shooters were necking up Grendel brass back in, at least 06' or so as an PPC bolt face alternative to the 30BR cartridge. This whole concept is not new, anyone ever heard of the Barnes 308x1.5 or Remington 308x1.8? These have been around for 40 yrs.

[BjornF16]

In ELASTIC tissue, e.g., "flesh" and "guts," the temporary wound cavity makes no significant contribution to the terminal effects. The temporary wound cavity only makes a significant contribution in INELASTIC tissues, e.g., brain, bone, liver.

That has not been my experience with medium sized game...I've seen plenty of "mush" in elastic tissue. I'm not sure I've ever seen temporary wound cavity being an issue in bone...it just breaks, fragments or has a hole in it as a result of direct impact.

7mm Rem Mag in chest cavity of a big Axis deer is a prime example of internals being "mush"...139 GMX with 3250 fps mv; impact at ~2850 fps.

Of course, reasonable people can disagree, and there is no clear consensus. It is still being debated in military circles.

According to Col. Fackler it is the permanent cavity which represents the wound mechanism, and the wounding effects of the temporary cavity are generally exaggerated. For example, some of the human parts like lungs, blood vessels bowel walls, etc., are elastic enough and tolerate stretching. Of course, solid tissue such as liver may not be so resilient.

There is a general impression that sonic waves set up by relatively high speed bullets could kill by damaging a large number of nerves through shock. This was refuted by Col. Fackler who opined that there was no solid evidence for this conclusion as the pressure peak of about 100 atmospheres had a duration of only two microseconds. It, therefore, did not move or harm the tissues.

The real fact is that the wound size may be independent of the muzzle velocity. For example, the bullet of mid to late 19th century had the velocity of around 400 m/s (which is low by present standards), but it produced large permanent and temporary cavities as the bullet was made of lead which deformed on striking the target, thus increasing its area and capacity for tissue disruption while the high mass ensured that it retained its capacity to penetrate.

The fact is that the real parameters which one should look for in a rifle are both the mass and the velocity of the bullet -and not velocity alone at the point of impact. To quote Col Fackler, The potential for tissue disruption depends on mass and velocity realisation depends on bullet construction, shape and interaction with target tissue, the type of tissue it hits. You can't say that a certain velocity in every case will give an X amount of damage.

http://www.defencejournal.com/april98/bulletwound.htm

While not a primary wounding mechanism, the secondary effect of wounding through tissue expansion is worthy of further study as both an aid to future ammunition design and firearm forensic investigations.

http://www.brassfetcher.com/Wounding%20T...ansion.pdf

"The size and the shape of the temporary cavity depend on the amount of kinetic energy lost by the bullet in its path through the tissue, how rapidly the energy is lost, and the elasticity and cohesiveness of the tissue. The maximum volume and diameter of this cavity are many times the volume and diameter of the bullet. Maximum expansion of the cavity does not occur until some time after the bullet has passed through the target. [Emphasis added.] The temporary cavity phenomenon is significant because it has been found to be the most important factor in determining the extent of the wounding in an individual in regard to the interaction of a bullet with the body. In the case of low-velocity missiles, e.g., pistol bullets, the bullet produces a direct path of destruction with very little lateral extension within the surrounding tissues. Only a small temporary cavity is produced. To cause significant injuries to a structure, a pistol bullet must strike that structure directly. The amount of kinetic energy lost in the tissue by a pistol bullet is insignificant to cause the remote injuries produced by a high-velocity rifle bullet.

http://kenrahn.com/JFK/Scientific_topics...speed.html

[Klem]

I agree with Bjorn's premise...I know what I have seen from hunting game over the years using several calibres. That includes using the Blackout both supersonic and subsonic with the following loads;

Supersonic;
110VMax Hornady
110TSXT Barnes
125TNT Speer
155gn (plinking only)

Subsonic
110TSXT Barnes (non-cycling for super-quiet)
210Hybrid Hunting/Match
220SMK Sierra
220RN Sierra
220RN Hornady
220JSP Outlaw State
225SMK Sierra

The potential energy contained in these loads is a clumsy correlation with the expected effects on the target. This is because they all exit the animal taking all that valuable energy with them. What's left is a crush trail and sometimes a laser beam and sometimes a tumble through.

No blood shock trauma as in other supersonic calibres. No instant 'lights-out'. Consensus on the Blackout forum which I follow is that projectiles across the board are not doing the caliber justice. The only supersonic bullet designed specifically for the Blackout is the Barnes 110gr 'Black Tip'. I have yet to try this so cannot comment.

Le-High subsonic 30cal hunting projectiles are designed to expand on hitting flesh. They have a deep hollow with 3 serrated claws. An expander .17cal rd is recommended. I have never tried these either so cannot comment.

The 220gr Outlaw State has serrations down the side and a thin jacket to aid in deforming. My experience is that might be the case but I have never recovered a round from an animal to know for sure. It exits and keeps going. A number have bounded off on being shot so there's no kinetic shock instant incapacitation happening.

Supersonic Blackout is slow and that translates into over-penetration with projectiles designed to expand acting like monoliths.

Subsonic Blackout is only 3/5 the potential chamber pressure so that means an under-load going even slower than supersonic. 220gr sound impressively big (and it is) but it's really just a handgun round acting like a FMJ hitting a target at 100M...what do you expect? Subsonic is all down to shot placement with the current projectile offerings. I imagine actual handgun rounds causing more damage with their deep hollow points and being specifically design for subsonic use.

[drykilned]

Does anyone know what has happened to the 30ARX? I need any available info on building one with parts from anyone other than ARX (TOO EXPENSIVE FOR A
COMMON RETIREE)

[Msalm]

Does anyone know what has happened to the 30ARX? I need any available info on building one with parts from anyone other than ARX (TOO EXPENSIVE FOR A
COMMON RETIREE)

What platform are you looking at doing it on? I've done something similar by reaming out a Howa Mini 7.62x39 chamber with a Grendel reamer. It increases performance over the standard 7.62 and SHOULD get the 125's up to 2650's or so (hoping). Do some research on the 30 Major...same basic round used in benchrest.

[Cornbread]

Does anyone know what has happened to the 30ARX? I need any available info on building one with parts from anyone other than ARX (TOO EXPENSIVE FOR A
COMMON RETIREE)

You might look into the 30 hrt. Basically 30 herret in ar platform based on necked up 6.8 case. Ballistics beats the grendel based 30 wildcat due to the higher operating pressure of the 6.8 case.

[sarky]

So it is an improved 7.62x39 that uses .308 bullets instead of .311?

[Msalm]

So it is an improved 7.62x39 that uses .308 bullets instead of .311?

The 30 arx is a 30 caliber (.308) Grendel case... I did something similar, but since I opened up an existing 7.62x39 Howa mini barrel, what I made was essentially an improved (30 degree shoulder) 7.62x39...I just accomplished that with a 6.5 Grendel reamer fitted with a 30 caliber pilot. Pretty much identical with .002" difference in bullet diameter.