Considering downsizing to 6 cm from 7 PRC

[huntnful]

I can see where you’re coming from.

To summarize:

Small is better camp argues shot placement trumps all else. Less recoil equals better shot placement, follow up, etc in field conditions. While a bigger bullet may destroy more tissue, it does not necessarily make up for bad shot placement, and up to a point does not mean significantly faster incapacitation.

Bigger is better camp argues they can shoot big magnums just fine and that all else being equal, a bigger bullet of similar construction will destroy more tissue giving more margin for error on borderline shot placement and faster incapacitation.



If anyone from big magnum camp wants to turn some heads, would be cool to see your shooting drill targets with magnum and non-magnum. Show us how well you can shoot the magnum.

One could argue that hunting mule deer you often have plenty of time to set up a perfect prone shot…personally that’s never been the case on a big deer for me. Which is why I need the most forgiving, trouble free, shootable from any position rifle.

Well said Will. Suppressors also seem to pair really well with the smaller cartridges/calibers also. And they seem to be an exceptional benefit as well!

 

[Article 4]

@Article 4, for the record I’m not arguing that ballistics gel is bad or that a bigger cartridge doesn’t add any additional wounding capability. Your initial posts, however, came across as a throwing out technical jargon to appear to have a strong case, but actually pulled that jargon from a non-ideal source which had the result of weakening rather than strengthening your argument.

The WP review article in post #179 is on point to your argument regarding pressure waves and trauma. How to extrapolate from a 500 ft/lb enables shock conclusion to how the OPs experience would have gone had he shot a 300 RUM or had he used a 6 Creed instead of his 7 PRC is ultimately the question.

I am not a terminal ballistics expert nor do I expect to ever become one.

I jumped into this thread when I read your post that had a bunch of technical jargon, but seems to use that jargon as a hammer to impress, while the background source seemed less then ideal for answering the OPs question.

I’m not refuting your argument as meritless. But if we’re going to use ‘expert’ data, then those data should be explained in relatable terms to the non-experts here. And if you or I or anyone else can’t explain how an elastic-plastic strain-hardening model for gel deformation helps the OP decide if a smaller vs larger caliber would have helped in his situation, then we shouldn’t be writing those words.

Pretending to be an expert by using big words gets my hackles up since I assume you’re pulling the wool over my eyes. Clearly being able to explain how the data and the science explain the OPs results and how a bigger (or smaller, or broadhead, etc) would have resulted in a better outcome demonstrated true expertise.

Been fun chatting back and forth, but now back to my day job where my boss consistently expects me to be a ‘expert’ in what I do. Sadly it’s not hunting.

Appreciate that

I am not an expert and don't propose myself as such. Those words have never come out of my mouth on these subjects. Nor do I pretend. Sorry about your hackels, mine get up from time to time too I guess. F-ing human traits LOL

I do post a lot of my experience and a lot of what I research - I find it to be valuable and I share it. Much as some others do. If that means using terms that some don't get or think is fine, so be it...hope it motivates them to look it up and find out.

Big words are a relative term. Since no one is an expert, you or me, is setting an expectation of how I "should" present it realistic?

I did explain the thought process - is there an expectation that it is tailored to each person? Probably not gonna happen

Relatable terms? I guess I wonder what that would be as everyone has a different level of understanding.

Yeah, I have a day job too and sometimes that gets in the way - dang it.

 

[JollyRoger]

I have a tikka I rebarreled with a 7 PRC. After finishing an AZ elk hunt this week and having a rodeo due to not being able to spot my hits for shit from a non prone position, I’ve decided I need to downsize my caliber.

So I’m considering rebarreling to a 6cm. But have a couple questions from guys who have done this:

- will be running suppressor so want barrel to be 18 or 20 max - what velocities could I expect shooting the 108 match ammo?

- what’s the max terminal range running a shorter barrel (18-20)? I’d really like to be able to stretch to 800 on elk- is this round capable of this?

I went through a similar progression over a few more years. Started a few years ago with a Tikka 7mm Rem Mag that I really liked. But ended up seeing how beneficial smaller calibers were. Eventually I had a 6CM built and I absolutely love this thing.

My set up has a 20” barrel, with suppressor. I’m getting ~2866 at the muzzle with factory 108 ELD-M. So far I’ve killed a nice buck and a few coyotes with it. I took it elk hunting but didn’t get any shots on them this year.

One thing to note, I believe you’ll need a new bolt for the 6CM since your PRC uses a magnum bolt face.

 

[Article 4]

I went through a similar progression over a few more years. Started a few years ago with a Tikka 7mm Rem Mag that I really liked. But ended up seeing how beneficial smaller calibers were. Eventually I had a 6CM built and I absolutely love this thing.

My set up has a 20” barrel, with suppressor. I’m getting ~2866 at the muzzle with factory 108 ELD-M. So far I’ve killed a nice buck and a few coyotes with it. I took it elk hunting but didn’t get any shots on them this year.

One thing to note, I believe you’ll need a new bolt for the 6CM since your PRC uses a magnum bolt face.

6 cm and PRC have different bolt faces. 473 and 532 respectively

At 800 yards if you hit vitals, likely kill. Hit big bone, maybe and if you believe in energy as a determinant around 850 +/- lbs
Likely somewhere in the high 2700 to mid 2800s

 

[mlevimadden]

Yes.. But switch to a 115 Dtac NR and practice, practice, practice!

What makes your prefer the 115 DTAC NR's over the 108 ELDM's?

 

[WyldGoose]

...the rub comes in when you/we get away from a productive conversation and use words and tactics that are finite and seen as bullying and emotional name calling.

lol

 

[LONE HUNTER]

Well said Will. Suppressors also seem to pair really well with the smaller cartridges/calibers also. And they seem to be an exceptional benefit as well!

Not going deaf is mucho awesome. Anyone with severe tinnitus and hearing loss likely will agree!

 

[fwafwow]

In post 183, @Bluefish said "I have not read anyone saying gelatin isn’t the best thing we have to compare wound potential." You replied "People in this thread have said it" and I asked in which posts.

Post 13 refers to energy of bigger bullets
post 19 refers to ballistic gel not meaning much
post 20 talks about energy being false
Post 82
Post 87 refers to it - gelatin as a measure of performance
Post 122 -

maybe there is more but I dont have the want to read the entire thread over

I don't think any of the above question the use of ballistic gelatin as a simulate. A couple of the posts you cite do question your use of pictures of balistic gelatin, and whether how you showed pictures was accurate or not.

[snip]

Here is another good study to read about it

Influence of impact velocity and impact attack angle of bullets on damage of human tissue surrogate —— ballistic gelatin - PMC

Terminal performance of a bullet in human body is critical for the treatment of gunshot injury and optimization of bullet design. The effects of the impact velocity (v0) and the impact attack angle (δ0) of the bullet on its terminal performance was ...

pmc.ncbi.nlm.nih.gov

Talks about gelatin, both temporary and permanent cavities, and angles affecting the outcome. Uses some measuring equipment as well.

I'm not trying to nitpick, and maybe my reaction to you posting studies was similar to @Runwilderness - in that it suggests (at least to me) that you can say fairly clearly and succinctly "study x analyzed whether y happens under z circumstances and the authors demonstrated a, b and c - please see text accompanying footnotes 1, 2 and 3."

I decided to start with the first study you posted. I'm about 3 pages in and I'm not (at least yet) seeing how this study relates to the three parts of your premise (other than this study uses ballistic gelatin, and I don't think anyone is really questioning the use of gelatin as a way to try to simulate real world results). Do you mind dumbing it down for me - maybe pointing me to the language or the page, and which of the other two parts of your premise it supports?

 

[Article 4]

In post 183, @Bluefish said "I have not read anyone saying gelatin isn’t the best thing we have to compare wound potential." You replied "People in this thread have said it" and I asked in which posts.

I don't think any of the above question the use of ballistic gelatin as a simulate. A couple of the posts you cite do question your use of pictures of balistic gelatin, and whether how you showed pictures was accurate or not.

I'm not trying to nitpick, and maybe my reaction to you posting studies was similar to @Runwilderness - in that it suggests (at least to me) that you can say fairly clearly and succinctly "study x analyzed whether y happens under z circumstances and the authors demonstrated a, b and c - please see text accompanying footnotes 1, 2 and 3."

I decided to start with the first study you posted. I'm about 3 pages in and I'm not (at least yet) seeing how this study relates to the three parts of your premise (other than this study uses ballistic gelatin, and I don't think anyone is really questioning the use of gelatin as a way to try to simulate real world results). Do you mind dumbing it down for me - maybe pointing me to the language or the page, and which of the other two parts of your premise it supports?

Yeah look, i hear you although nitpicking does seem to be a lot of what is taking place. It happens often when we take things out of context and sentence by sentence. Me included.

Your first two points are moot. Answered already

Sorry things aren't exactly as you want them...I didn't do the studies, like you i read them and as many of them as I can and make a judgement based on the body of evidence - not on whether this one study absolutely defines the/every answer. Haven't found "the one" that confirms it definitely either way - have one? Happy to read it.

I already answered a lot of that.

Most of us believe and are good with gel as a medium. Its the best tool we have outside animals and humans. Take a look at post #20 - I quote "Brother have you listened to any of the S2H podcasts about bullet lethality? Showing a picture of ballistic gel isn't doesn't mean much."

I have answered all of that completely, and Ill add this one, which does a pretty good job supporting Gel, incapacitation, energy, and hydrostatic shock. All of which is discussed in this thread.
https://apps.dtic.mil/sti/tr/pdf/ADA526059.pdf
I like it as it takes evidence from 39 studies, cites them, and adds their conclusions which are going to be better than mine or anyone else's I have seen. It opens relating to much of what we are discussing.

Abstract: This paper reviews the scientific support for a ballistic pressure wave radiating outward from a penetrating projectile and causing injury and incapacitation. This phenomenon is known colloquially as “hydrostatic shock.” The idea apparently originates with Col. Frank Chamberlin, a World War II trauma surgeon and wound ballistics researcher. The paper reviews claims that hydrostatic shock is a myth and considers supporting evidence through parallels with blast, describing the physics of the pressure wave, evidence for remote cerebral effects, and remote effects in the spine and other internal organs. Finally, the review considers the levels of energy transfer required for the phenomenon to be readily observed.

I applaud you reading them. Ill read anything anyone wants to send me too. Keep reading if you like and come up with your own answer rather than relying on me or mine.

 

[mxgsfmdpx]

TK421 guy scrubbed his posts but back in the day i'm sure he'd have posted up some 7rm targets. Haven't really seen it from others though?

I'm probably remembering poorly, but wasn't nearly all of his "target and groups" posted from either a bench at a range or prone in the field on a flat range?

 

[wind gypsy]

I'm probably remembering poorly, but wasn't nearly all of his "target and groups" posted from either a bench at a range or prone in the field on a flat range?

He posted a lot of tripod groups too. More Kraft drill type stuff than Carls hunting drill type stuff from the "equip vs practice" thread.

 

[ARK_Ginger]

Since I promised you some links.

https://www.researchgate.net/publication/5759573_Ten_Common_Myths_of_Ballistic_Injuries

chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://gundata.org/images/fbi-handgun-ballistics.pdf
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://thinlineweapons.com/IWBA/2001-Vol5No2.pdf

https://www.researchgate.net/publication/21037128_Gunshot_wounds_I_Bullets_ballistics_and_mechanisms_of_injury

I hear you

As stated - my premise has never been that a big enough hole in something kills it.

My argument is: adding large amounts of kinetic energy around the hole increases the odds of killing exponentially. Additionally, when the hole may not be perfectly placed, the large amount of energy may have a killing result when it is large enough and powerful enough to damage the organs and create shock to the system. shutting down the nervous system and in some cases liquifying the organs.

Matching was never the idea. The OP was considering going from a 7 to a 6mm. the two photos were not meant to directly compare a bunch of the same. They were meant to support that staying with bigger bullets for hunting will penetrate better, transfer more energy, and damage more tissue than smaller.

Exponentially? LOL. The additional energy is meaningless if the elastic limit of the tissue hasn't been exceeded. The 'added' damage to organs won't likely lead to decreased incapacitation time. IF the ballistic pressure wave is close enough to the nervous system it could cause temporary or permanent incapacitation.

Here's a highlighted portion from a study you linked when we had a similar discussion earlier this year.
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://medcoeckapwstorprd01.blob.core.usgovcloudapi.net/pfw-images/borden/conventional-warfare/Chap4Pages13-25.pdf

here are a few more to read through if you have the time. They also point to numerous other studies that I am in the process of reading as references - I havent read them all yet nor do I expect them to come right out and say, these results are absolutely definitive and 100% true. Havent found a study that will.

This is one of the most recent done by PhDs in ballistics and physics at West Point - specifically talking about incapacitation - they cite 39 other studies not listed below as some of their references.

https://apps.dtic.mil/sti/tr/pdf/ADA526059.pdf

Here are some others - just 28 more citations.

• Liu Y.Q., Wang Z.G., M Y.Y. People's Military Medical Press; Beijing: 1991.
• Kneubuehl B.P., Coupland R.M., Rothschild M.A., et al. Springer; Berlin: 2008.
• Li M.A., Wen Y.K., Zhang J.B., et al. 30th International Symposium on Ballistics. California, USA. 2017. Numerical analysis of rifle bullet impact armor covered human torso.
• Su Z.L. Third Military Medical University; 2012. The Characteristics and Mechanism of Remote behind Armor Blunt Brain Trauma in Swine.
• Chen Y., Miao Y., Xu C., et al. Wound ballistics of the pig mandibular angle: a preliminary finite element analysis and experimental study. J Biomech. 2010;43:1131–1137. doi: 10.1016/j.jbiomech.2009.12.009.
• Janzon B., Seeman T. Muscle devitalization in high-energy missile wounds, and its dependence on energy transfer. J Trauma. 1985;25:138–144. doi: 10.1097/00005373-198502000-00009.
• Jussila J., Kjellström B.T., Leppäniemi A. Ballistic variables and tissue devitalisation in penetrating injury--establishing relationship through meta-analysis of a number of pig tests. Injury. 2005;36:282–292. doi: 10.1016/j.injury.2004.09.010.
• Breeze J., James G.R., Hepper A.E. Perforation of fragment simulating projectiles into goat skin and muscle. J Roy Army Med Corps. 2013;159:84–89. doi: 10.1136/jramc-2013-000065.
• Appleby-Thomas G., Hameed A., Fitzmaurice B., et al. 2016. On the Selection of Tissue Simulants for Ballistic Testing. 29th International Symposium on Ballistics. Edinburgh, Scotland, UK.
• Riva F., Mattijssen E.J.A.T., Kerkhoff W. Rifle bullet deflection through a soft tissue simulant. Forensic Sci Int. 2018;291:199–206. doi: 10.1016/j.forsciint.2018.08.024.
• Riva F., Lombardo P., Zech W.D., et al. Individual synthetic head models in wound ballistics - a feasibility study based on real cases. Forensic Sci Int. 2019;294:150–159. doi: 10.1016/j.forsciint.2018.11.020.
• Xiong M., Qin B., Wang S., et al. Experimental impacts of less lethal rubber spheres on a skin-fat-muscle model. J Forensic Leg Med. 2019;67:7–14. doi: 10.1016/j.jflm.2019.07.009.
• Mabbott A., Carr D.J., Champion S.M., et al. 27th International Symposium on Ballistics. Freiburg; Germany: 2013. Comparison of 10% gelatine, 20% gelatine and Perma-Gel for ballistic testing.
• Jain P., Kaur S., Bhatacharjee D., et al. Hyderabad; India: 2019. Effect of Various Backing Materials on BABT in Ballistic Evaluation of Body Armour. 31st International Symposium on Ballistics.
• Korać Z., Kelenc D., Hančević J., et al. The application of computed tomography in the analysis of permanent cavity: a new method in terminal ballistics. Acta Clin Croat. 2002;41:205–206.
• Jin Y., Mai R., Wu C., et al. Comparison of ballistic impact effects between biological tissue and gelatin. J Mech Behav Biomed Mater. 2018;78:292–297. doi: 10.1016/j.jmbbm.2017.11.033.
• Liu L., Jia Z., Ma X.L., et al. A spherical cavity expansion model of large elastic deformation and its application to ballistic gelatin penetration problems. Int J Impact Eng. 2014;71:106–116. doi: 10.1016/j.ijimpeng.2014.04.007
• Schyma C., Madea B. Evaluation of the temporary cavity in ordnance gelatine. Forensic Sci Int. 2012;214:82–87. doi: 10.1016/j.forsciint.2011.07.021.
• Wen Y., Xu C., Jin Y., et al. Rifle bullet penetration into ballistic gelatin. J Mech Behav Biomed Mater. 2017;67:40–50. doi: 10.1016/j.jmbbm.2016.11.021.
• Schyma C.,Hagemeier L.,Greschus S., et al.Visualisation of the temporary cavity by computed tomography using contrast material. Int J Leg Med. 2012;126:37–42. doi: 10.1007/s00414-010-0546-1.
• Schyma C.W. Colour contrast in ballistic gelatine. Forensic Sci Int. 2010;197:114–118. doi: 10.1016/j.forsciint.2010.01.002.
• Schyma C., Greschus S., Urbach H., et al. Combined radio-colour contrast in the examination of ballistic head models. Int J Leg Med. 2012;126:607–613. doi: 10.1007/s00414-012-0704-8.
• Bolliger S.A., Thali M.J., Bolliger M.J., et al. Gunshot energy transfer profile in ballistic gelatine, determined with computed tomography using the total crack length method. Int J Leg Med. 2010;124:613–616. doi: 10.1007/s00414-010-0503-z.
• Jussila J. Measurement of kinetic energy dissipation with gelatine fissure formation with special reference to gelatine validation. Forensic Sci Int. 2005;150:53–62. doi: 10.1016/j.forsciint.2004.06.038.
• Mo G.L., Li Z.X., Wu Z.L. A theoretical model of non-deforming bullets penetrating ballistic gelatin. Int J Impact Eng. 2018;114:105–110. doi: 10.1016/j.ijimpeng.2017.12.004.
• Mo G.L., Jin Y.X., Wang X.J., et al. Ballistic modelling and experimental studies of rifle bullets penetrating ballistic gelatin. J Beijing Inst Technol (Soc Sci Ed) 2018;38:1244–1251. doi: 10.15918/j.tbit1001-0645.2018.12.006.
• Lynch N.J., Pitcher P. 29th International Symposium on Ballistics. Edinburgh, Scotland, UK. 2016. The influence of yaw on the perforation of fragments.
• Bartlett C.S. Clinical update: gunshot wound ballistics. Clin Orthop Relat Res. 2003;408:28–57. doi: 10.1097/00003086-200303000-00005.

Once again, if some of the folks here expect a scientist to come out and say, my evidence is irrefutable and as such is the only answer, are going to be deeply disappointed. No scientist would ever do that.

And according to some here who think theirs is the ONLY answer, none of this matters. I am good with people thining what they think - i think what I think based on personal experience and some of this data, not emotion. Nor do I expect any credit for actually doing my own reading and studying.

But of course, this is all Fuddery according to some flat earth, gravity doesn't exist, and unicorns are real kinda people and any differing opinion than what some here think is true is complete BS.

I'll make the same response as I did in June to this paper.
"This paper seeks to support the notion of ‘hydrostatic shock’, but it fails to prove how meaningful it is to incapacitate as it relates to time since it is just simply a review of the existing literature on ballistic pressure waves. It even fails to prove that hydrostatic shock would be the correct terminology for the observed effect, since ballistic pressure wave is a much more accurate description.

If someone wanted to use this paper to ‘prove’ hydrostatic shock exists I guess you could. I think it would be more accurate to say that it shows there is research measuring tissue damage from ballistic pressure waves/the temporary stretch cavity and cause damage at energy transfer levels above 300ft/lb and is more evident above 600ft/lb, but how this aids in time to incapacitation is undetermined currently."