10mm ballistics in a 3+" barrel vs a 6" barrel

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Fivesense

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I compared ballistics of the 10mm in a 3.77 inch (Glock 29) barrel to that of a 6.02 inch (Glock 40). For Buffalo Bore 180 gr., is it possible that it's less than 150 fps? The differential seems to decrease the lower the weight of the bullet. What am I misreading, or am I?

10mm ballisticsbytheinch.com
 
If you look at the muzzle energy graph off of that link you can see that it's about 700 ft lbs of energy for a 4" barrel vs. Just over 800 ft lbs for 6 in. I think the velocity difference or energy difference is all a matter of perspective. It's what a 14% increase in energy.
 
It's not obvious to me how bullet weight alone would impact the difference--but I do know from data I've collected that propellant (and most likely, propellant burn rate) is a significant factor. Loads using faster powders won't exhibit as much gain from barrel length as do loads using slower burning powder. It is perfectly possible that the performance you're seeing (or the statistics you're seeing) for lighter bullets is due, in part, to the loads for those bullets being concocted with faster powders.

That's a bit of a stretch in assumptions, but it's plausible.

All that bull being said, reflect on what 150 fps is in terms of a percentage increase--it's very roughly somewhere in the neighborhood of 10% am I right? The point here is that muzzle energy (a meaningless statistic in the view of many 9mm shooters I suppose) goes as the square of the velocity--so a 10% increase (1.10 x) is about a 20% increase in energy (1.1 * 1.1 = 1.2).

Now of course "with today's modern ammunition" .380 ACP is just as lethal as 10mm, so it's no biggie. :cool:
 
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Now of course "with today's modern ammunition" .380 ACP is just as lethal as 10mm, so it's no biggie.
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I know you were joking but it does bring up what I think is an interesting point. Common sense would say that a heavier projectile propelled by more energy would do more damage but how would one quantify the lethality of each cartridge scientifically? There is the LD50 for toxology and tables for radiation exposure - intensity, type and duration but what do people use for getting shot?

I bet there aren't too many volunteers lining up for that kind of research :p
 
I don't load for my 10mm's but do for my hunting rifles. With lighter 150 gr bullets the difference between 308 and 30-06 is a lot closer than with heavier bullets.

The difference in muzzle velocity between 20" rifles and 22-24" rifles is a lot closer with 150 gr bullets than with 180 gr bullets. At least based on my observations as bullet weight goes up barrel length and case capacity are more important. I'd think it would be the same with 10mm.

I shoot 200gr Double Tap ammo advertised at 1300 fps from a G20 and 1250 fps from a G29. I've chronographed them in my G20 and got exactly 1300 fps. I haven't had the G29 as long and have not actually shot any over the chronograph, but don't expect it to be too far off.

Now of course "with today's modern ammunition" .380 ACP is just as lethal as 10mm, so it's no biggie.
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That depends on what you're shooting. Against human threats I don't think this comment is terribly wrong. I'd feel just fine with 9mm+P loads if I had to defend myself from 2 legged predators. But I carry the 10mm as my woods hiking and camping gun in bear country. A 200 gr bullet at 1250-1300 fps might not make any difference against a grown man, but would be an advantage if I had to shoot a 300-400 lb bear. I sleep better anyway.
 
Thank you for these responses- very educational.

Considering the minimal difference in fps and relative difference in foot pounds of energy, I like the idea of the subcompact 10mm (Glock 29), especially since I shoot my G26 marginally better than my G17. Recoil will be a factor in the smaller gun, but not an eliminating one.
 
Thank you for these responses- very educational.

Considering the minimal difference in fps and relative difference in foot pounds of energy, I like the idea of the subcompact 10mm (Glock 29), especially since I shoot my G26 marginally better than my G17. Recoil will be a factor in the smaller gun, but not an eliminating one.
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That is awesome. I tend to do better with a longer sight radius. Still, it's hard to go wrong with a 10mm. I love that chambering more than I love Key Lime Pie and I'm a man who loves him some Key Lime Pie.
 
Looking at that chart tells me to buy Buffalo Bore 180-grain
and forget the rest...

The only downside to that chart is they did it a long time ago,
and there are a heck of a lot more 10mm rounds available now...
I'd lay odds that Double-Tap would chrony similarly to BB.

I'd love to see how Hornday CD worked in there, too :)
 
Considering the minimal difference in fps and relative difference in foot pounds of energy, I like the idea of the subcompact 10mm (Glock 29), especially since I shoot my G26 marginally better than my G17. Recoil will be a factor in the smaller gun, but not an eliminating one.
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I don't think I'd ever give much weight in firearm selection to these somewhat 'marginal' matters. So many other factors are so vastly more important. In fact, for me, getting the last drop of performance out a cartridge is just a silly exercise in with little to no practical benefit--it's an entertainment/enjoyment activity, but not one that has any other value.

In selecting a carry weapon, "how fast can I draw, present, fire and hit" trumps just about every other thing I can think of. Right behind "how fast can I get to cover", which is weapon-independent. :)

I have one handgun I can consistently draw and hit faster and more accurately than anything else--my MP 45 Compact. It's like my miracle machine. I should carry it exclusively, really. But for whatever reason I just like to carry the G29 most of the time...maybe because it makes me feel good. I carry it loaded with handloads that I've 'handcrafted' one at a time, molly-coddled loads I do indeed trust to come thru in the bank or liquor store or mall when it all goes bad. It's a great little gun, IMO. Quite possibly the most horrific aesthetic firearm atrocity ever manufactured besides the Nambu or pink plastic pistols, but a great little disaster of aesthetics.
 
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Not to challenge Firearms by the Inch numbers, but I wonder if they truly derive them from shooting. Also, I don't the think the "old school" method of saying handguns lose about 50 fps per inch and rifles 100 fps per inch holds true with high pressure, low capacity cases and solid barrels versus the old days of larger case capacity, BC gaps, and powders with quite different burning properties.
I say this because I own a Glock 29 and a Glock 20, neither has ever shot a hand load, nor has either ever shot anything but Underwood's most excellent selection of FULL HOUSE 10mm!
In actual chronograph testing I recorded numbers as follows:

Underwood 10mm 155gr XTP G29 3.77" bbl = 1,434 fps (avg) / 708 fpe
Underwood 10mm 155gr XTP G20 4.6" bbl = 1,524 fps (avg) / 800 fpe
108 fps / .83" polygon rifling (Glock)
Underwood 10mm 155gr XTP G20 5.1" LWD bbl = 1,555 fps (avg) / 832 fpe
90 fps / 1.33" polygon:cut rifling (Glock vs LWD)

UW 10mm 135 gr JHP G29 3.77" bbl = 1,482 fps (avg) / 659 fpe
UW 10mm 135 gr JHP G20 5.1" LWD bbl = 1,615 (avg) / 782 fpe
133 fps / 1.33" polygon:cut rifling (Glock vs LWD) This equates to 100 fps PER INCH of barrel reduction when shot across a chronograph!

I have recorded actual chronograph numbers for many of UW's other 10mm offerings, but only from the G20 4.6" barrel.
These numbers also include a 22# spring and solid guide rod in the G20 and 24# multi-spring, multi-part guide rod from LWD in the G29.

I believe this is why we are seeing the introduction of longer barreled 10mm's...the hunting community has shown that 6" barrels really bump the power of the 10mm, and this is validated by actual chronograph numbers. While I cannot recall exactly where I've seen numbers from 6" barrels, there are hand loaders pushing over 900 lb-ft KE with 6" barrels and medium weight bullets, with 200 grain pushing and exceeding 800 lb-ft.
 
Interesting. I carry my G29 with UW 10mm 200 XTP rated at 1250 fps out of 5" barrel.

I figured about 1100+ fps out of my 3.77" barrel.
 
Common sense would say that a heavier projectile propelled by more energy would do more damage but how would one quantify the lethality of each cartridge scientifically?
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^^^^^^^Shot placement^^^^^^^^^^^^^^^

A shot in the right place with even a lethargic round will be lethal. Your question is subjective.
 
10mm ballistics in a 3+" barrel vs a 6" barrel
I compared ballistics of the 10mm in a 3.77 inch (Glock 29) barrel to that of a 6.02 inch (Glock 40). For Buffalo Bore 180 gr., is it possible that it's less than 150 fps? The differential seems to decrease the lower the weight of the bullet. What am I misreading, or am I?
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If we look at the chart from BBTI it shows the 180 gr. BB round doing 1338 fps. from a 4" barrel (which is closer to the 3 3/4" barrel you have with the G29). then you have the same round at 6" doing 1428 fps. So the difference in velocity is 90 fps. which is about right. The velocity is 1374 from the Colt "Real World Weapon" shown below. All that is about right.

If you read the chart from left to right you can see that the velocities of the bullets, both lighter and heavier, vary quite a bit. This is because of their charges or loadings, the amount and type of powder in the charge. So we see that the Federal 180 gr. load is slower than the BB even though they are the same weight. This is not due to the weight of the bullet but to the charge and the length of the barrel.

We can also see that the same Federal Hydra Shok 180 gr. is slower than the Hornady 200 gr. XTP in the same barrel length. The latter holds a more powerful charge.

A 180 gr. bullet that begins slower in a 4" barrel will continue to be slower in all barrel lengths (usually).

So I think that's what you are looking at. Let me know if I don't get the question.

tipoc
 
As noted above, placement is the key... and just about any 10mm round will penetrate deeply enough to do serious damage.

That said, with handguns, almost no bullets move quickly enough to cause grave tissue damage (i.e., via a temporary wound cavity) -- that takes rifle velocities. Temporary wound cavities from handgun rounds seem to have almost no effect DURING the shootout. When rifles are used, the effect of temporary wound cavities are more significant and can have immediate effects in slowing or ending the conflict.

Those things said, barrel length and velocity may NOT be a big deal as long as the shooter puts the round where it needs to be put. With handguns, the size of the bullet (caliber) and the tissue it directly damages is arguably a bigger deal than the bullet's weight, but unless the wound track/hole made is in the right spot -- perhaps a hit to the central nervous system -- the other guy may still stop you before you stop him...

.
 
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