firewrench044
New member
9MM FMJ - flat base or hollow base ( jacketed, not cast or plated )
what are the advantages and disadvantages of one over the other
what are the advantages and disadvantages of one over the other
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9MM- FMJ flat base or FMJ hollow base
- Thread starter firewrench044
- Start date
The Win 115 hbfmj provide a longer bearing surface over their 115 fmj counterparts. They are one of the most accurate bullets I have loaded in 9mm. They used to be /are the bullets Win was loading in Q4172 white box loads, one of the most accurate factory loadings personally used.
The hollow base may also help in the accuracy with various bore diameters in 9mm. Just guessing that part.
Have loaded lots of em over the years, and prefer them over the flat base version.
The hollow base may also help in the accuracy with various bore diameters in 9mm. Just guessing that part.
Have loaded lots of em over the years, and prefer them over the flat base version.
Zeke pretty much covered it. The differences are longer length and more bearing surface, and more weight forward on the HB verses a shorter length per same weight in the FB version.
I shoot both and have noted there is a little difference in the two but it mostly equated to a bit higher velocity in the FB version for the exact same load which gave a bit more spread in the group than the HB version. However simply dropping the load by a couple tenths of a grain pulled them into almost identical group sizes.
The FB version would possibly be a better choice for a shorter case like say the .380, or if your loading something like the 147gr where you might be more concerned about pressure or a compressed load with a particular powder as the HB version will need to be seated a touch deeper to maintain the correct OAL.
I shoot both and have noted there is a little difference in the two but it mostly equated to a bit higher velocity in the FB version for the exact same load which gave a bit more spread in the group than the HB version. However simply dropping the load by a couple tenths of a grain pulled them into almost identical group sizes.
The FB version would possibly be a better choice for a shorter case like say the .380, or if your loading something like the 147gr where you might be more concerned about pressure or a compressed load with a particular powder as the HB version will need to be seated a touch deeper to maintain the correct OAL.
On paper, the hollow base gives more bearing surface (as already mentioned), which is better for accuracy at short range (the distances where you're most likely shooting). The drawback of the hollow base is, being longer, it is more prone to rotational instability (gyroscopic precession, technically); and thus, will start to tumble sooner as it makes its journey downrange. Not likely to be an issue, unless you're shooting at something like 50 yards or more.
In more realistic terms, the hollow base is a good idea for the small 115's. They realize a considerable advantage with some extra bearing surface.
In more realistic terms, the hollow base is a good idea for the small 115's. They realize a considerable advantage with some extra bearing surface.
Last edited:
firewrench044
New member
Thanks
That is the information I needed
That is the information I needed