55gr or 62gr and FMJ or SP to stockpile?

EddieZoom said:
Any resources you can point to that compare terminal performance ? I kinda get the idea that M855 might be less effective since it may pass through bad guys but could it really be that much of a difference ?
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There were a lot of reports from Somalia about M855 ice picking, so the DoD did a study. It’s in large part due to the bullet design needing some yaw upon transition from external ballistics(flight outside barrel) to terminal ballistics. Without that yaw, the bullet was much more likely to stay intact and pierce straight through without fragmenting or tumbling.

When M855 does fragment, it’s pretty decent. But it’s just not consistent.

It also has a high velocity threshold like M193. M855A1 has a low velocity threshold for fragmentation.

Also of interest: https://apps.dtic.mil/sti/pdfs/ADA530895.pdf
 
PappyM3 said:

There were a lot of reports from Somalia about M855 ice picking, so the DoD did a study. It’s in large part due to the bullet design needing some yaw upon transition from external ballistics(flight outside barrel) to terminal ballistics. Without that yaw, the bullet was much more likely to stay intact and pierce straight through without fragmenting or tumbling.

When M855 does fragment, it’s pretty decent. But it’s just not consistent.

It also has a high velocity threshold like M193. M855A1 has a low velocity threshold for fragmentation.

Also of interest: https://apps.dtic.mil/sti/pdfs/ADA530895.pdf
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Excellent. Thanks.
 
EddieZoom said:
Any resources you can point to that compare terminal performance ? I kinda get the idea that M855 might be less effective since it may pass through bad guys but could it really be that much of a difference ?
Click to expand...

Thank you for gently calling me out.

I am guilty of repeating what I've read so many times. That the 55 gr bullets are more likely to tumble whereas the 62 gr are likely to pass through inflicting only "ice pick" type wounds.

If anyone has any citations for this, it would be good.

PappyM3 said:

There were a lot of reports from Somalia about M855 ice picking, so the DoD did a study. It’s in large part due to the bullet design needing some yaw upon transition from external ballistics(flight outside barrel) to terminal ballistics. Without that yaw, the bullet was much more likely to stay intact and pierce straight through without fragmenting or tumbling.

When M855 does fragment, it’s pretty decent. But it’s just not consistent.

It also has a high velocity threshold like M193. M855A1 has a low velocity threshold for fragmentation.

Also of interest: https://apps.dtic.mil/sti/pdfs/ADA530895.pdf
Click to expand...

There is plenty of data showing the 62gr M855 out of 1:7 barrels does not yaw as much as would be ideal.

But is there anything showing the 55 gr M193 to be better in that respect??
 
dcmdon said:
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There is plenty of data showing the 62gr M855 out of 1:7 barrels does not yaw as much as would be ideal.


But is there anything showing the 55 gr M193 to be better in that respect??
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I’m not aware of research specific to that comparison. However, looking at previous work from Fackler, it doesn’t seem that M193 is as dependent on yaw in order to fragment, so it may be moot to determine whether how much yaw M193 exhibits in 1:7.
 
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