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  #1  
Old 05-03-2018, 12:46 AM
17tbs 17tbs is offline
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Default Have you seen this? 62gr BTHPM 0.862" .

HORNADY 62gr BTHPM with cannelure



Specifications and Features:
.224 Diameter
Boat Tail Hollow Point
.862" Long
Sectional Density 0.194
Ballistic Coeficient (G1) 0.355

Has anyone shot these?

https://www.midsouthshooterssupply.c...ure-1500-count

Last edited by 17tbs; 05-03-2018 at 12:49 AM.
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  #2  
Old 05-03-2018, 01:10 AM
MIBULLETS MIBULLETS is offline
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I'm curious too. I've had my eye on them for a while now but haven't purchased any yet.
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  #3  
Old 05-03-2018, 01:15 AM
hemiallen hemiallen is offline
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I wonder what twist is needed for them pushed to 3500 fps? I have seen individuals recommend 1:9, not sure if that is correct or a guess.

Thanks
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  #4  
Old 05-03-2018, 01:18 AM
Bill K Bill K is offline
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Default Have you seen this ? 62gr bthpm

Quote:
Originally Posted by hemiallen View Post
I wonder what twist is needed for them pushed to 3500 fps? I have seen individuals recommend 1:9, not sure if that is correct or a guess.

Thanks
I would say 1/9 to 1/7 twist would be a good one. Bill K
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  #5  
Old 05-03-2018, 02:02 AM
Bayou City Boy Bayou City Boy is offline
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I have an 8" twist Tikka T-3 Lite 22-250 that shoots them just fine.

I haven't had time to try them in it yet, but I have a 22-6MM Rem with a 12" twist barrel that shoots 60 grain Sierra HP bullets extremely well. However, the 60 grain bullets are shorter at .780" with no boat tail, but Sierra says 12" or faster twist for them in a 223 Rem sized case. Hopefully the speed of the 22-6MM will make a difference, but I'm not sure as they are almost 0.1" longer than the Sierra bullet.

Added Sierra's words on the 60 grain HP: For rifles, this is a high-velocity bullet designed to give precision accuracy with the explosive expansion of Sierra's Varminter-style construction. This bullet is at its best when fired from the larger-capacity cartridges, such as the 22-250 or 220 Swift in rifles with barrels having 1x14" twist rates, stabilizing easily for excellent long-range accuracy and effective expansion. Normally, 1x12" or faster twist rates work best for medium-capacity cases, such as the 223 Remington. These bullets are excellent for long-range varmint hunting. For handguns, although this bullet is of Hollow Point construction, we cannot recommend it for hunting purposes. This bullet has been very successful on half-size NRA Silhouette targets

-BCB
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Last edited by Bayou City Boy; 05-03-2018 at 02:07 AM. Reason: material added...........
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  #6  
Old 05-03-2018, 02:14 AM
17tbs 17tbs is offline
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Default Stability in 1 in 12" velocity needed

Based on a test named ballistics by the inch for .223 Reimngton barrel, it should not be optimal at 1 in 12" twist at 2960fps out of a 16.5" barreled bolt gun. A 1 in 8 seems to be optimal at that velocity according to those with experience here and referring to the JBM stability calculator.

At 5000 feet altitude it gets better if you can push it to 3700feet per second.

I would still recommend that you have a 1 in 10" twist to shoot at this altitude.

Borderline stable 30gr Kindler gold .172" and 69gr HPBTM Sierra bullets that shoot just fine in NM at 5000ft + shoot like a shotgun at sea level.

Air pressure above sea level can be calculated as

p = 101325 (1 - 2.25577 10-5 h)5.25588 (1)

where

101325 = normal temperature and pressure at sea level (Pa)

p = air pressure (Pa)

h = altitude above sea level (m)

Example - Air pressure at Elevation 10000 m
The air pressure at altitude 10000 m can be calculated as p = 101325 (1 - 2.25577 10-5 (10000 m))5.25588

= 26436 Pa = 26.4 kPa



Stability Input Data

Caliber: 0.224 in Bullet Weight: 62.0 gr
Bullet Length: 0.862 in Plastic Tip Length: 0.000 in
Muzzle Velocity: 3700.0 ft/s Barrel Twist: 12.0 in
Temperature: 59.0 °F Pressure: 24.90 in Hg
Output Data
Stability: 1.250
02-May-18 20:16, JBM/jbmstab-5.1.

So, based on that, I might try a few pulled down and hand loaded, but I won't bet they will perform well at or near sea level.

Last edited by 17tbs; 05-04-2018 at 05:55 AM.
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  #7  
Old 05-03-2018, 02:22 AM
Bayou City Boy Bayou City Boy is offline
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Quote:
Originally Posted by 17tbs View Post
Based on a test named ballistics by the inch for .223 Remote barrel, it should not be optimal at 1 in 12" twist at 2960fps out of a 16.5" barreled bolt gun. A 1 in 8 seems to be optimal at that velocity according to those with experience here and referring to the JBM stability calculator.
I'm talking about a 22-6MM Rem at roughly 3500 -3800 fps when I'm saying that I hope the extra speed will maybe make them work. If they don't, the Sierra 60's work just fine.

-BCB
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Yo no creo en santos que orinan.

Women and cats will do as they please. Men and dogs should relax and just get used to the idea.

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  #8  
Old 05-03-2018, 02:32 AM
17tbs 17tbs is offline
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BCB yep, if you note above, I account for 3700FPS.
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  #9  
Old 05-03-2018, 02:39 AM
Bayou City Boy Bayou City Boy is offline
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Quote:
Originally Posted by 17tbs View Post
BCB yep, if you note above, I account for 3700FPS.
I understand where you're coming from. On the flip side, I've found that the best ballistic calculators don't always tell a true story like actual trying does.

As I stated, its not a critical issue for me in the 22-6MM and the bullets I have on hand will get consumed in the 22-250 and in a couple of AR's, so its no big deal either way.

BTW - These are BTHP bullets and not plastic tipped bullets

-BCB
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I miss mean Tweets, competence, and $1.79 per gallon gasoline.

Yo no creo en santos que orinan.

Women and cats will do as they please. Men and dogs should relax and just get used to the idea.

Going keyboard postal over something that you read on the internet is like seeing a pile of dog crap on the sidewalk and choosing to step in it rather than stepping around it.

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  #10  
Old 05-03-2018, 02:48 AM
squirrel_slayer squirrel_slayer is offline
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man you gotta love the great BC wars! the slipperier the better!
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