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Discussion Starter · #1 ·
Is the length of the SS198/195 (27gr) the same as the SS197 (40gr)? The SS198 is just lighter because it has an aluminum core?

I always figured the size of a bullet was directional proportional to the weight of the bullet. But given the exotic material cores of some of the 5.7 rounds, I guess they can be the same size as traditional lead core bullets bullets weighing almost twice as much. Is my thinking correct here?
 

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Discussion Starter · #3 ·
This may sound snide but why dont you just pull two rounds 197 and 198 and mic them? I would assume that the coal of 197 and 198 is close
From what I can tell, they are about the same. But I am raising a larger point for discussion here. When not using lead in the core, but lighter materials, you can have a larger bullet than what you expect based on weight. I would think a 27gr projectile would be very small, but it is interesting that it can be even larger than a bullet almost twice its weight.

When something counters traditional logic, I think it makes for interesting discussion.
 

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Yeah the SS195/198 bullet is longer than the SS197 bullet. The excess length is hidden inside the case and reduces the volume inside of the case for the powder to burn, which helps to increase pressure and to a certain extent, velocity. Also the 195 and 198 are loaded hotter than the 197 as well.
 

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For your viewing pleasure

AE TMJ: .552" - They've revised the bullet on this in newer lots so it may be slightly longer
SS197SR: .688"
SS192/195/198: .815"
SS190: .835"

BTW factory rounds don't pull down very well in a kinetic bullet puller, had to get nasty with them. The SS197SR seems to have the softest lead compared to the AE TMJ.

 

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Discussion Starter · #7 ·
For your viewing pleasure

AE TMJ: .552" - They've revised the bullet on this in newer lots so it may be slightly longer
SS197SR: .688"
SS192/195/198: .815"
SS190: .835"

BTW factory rounds don't pull down very well in a kinetic bullet puller, had to get nasty with them. The SS197SR seems to have the softest lead compared to the AE TMJ.

See that is super interesting to me. The SS198 27gr is considerable longer and bigger than the SS197 which is over 50% heavier. Very interesting. So we have a lighter bullet that is a bigger projectile than the heavier bullet.
 

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See that is super interesting to me. The SS198 27gr is considerable longer and bigger than the SS197 which is over 50% heavier. Very interesting. So we have a lighter bullet that is a bigger projectile than the heavier bullet.
Correct because lead is a denser material than aluminum. The core of the 192/195/198 is aluminum (don't know what kind).

Just like solid copper rounds that are the same weight as a lead counterpart will be considerably longer as well.
 

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For your viewing pleasure

AE TMJ: .552" - They've revised the bullet on this in newer lots so it may be slightly longer
SS197SR: .688"
SS192/195/198: .815"
SS190: .835"

BTW factory rounds don't pull down very well in a kinetic bullet puller, had to get nasty with them. The SS197SR seems to have the softest lead compared to the AE TMJ.

Buffman always delivers! :shock:
 

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Buffman, thanks so much for posting this.

I have only shot the Fiocchi rounds:
Federal AE5728A, and
FNH SS197 SR.

I never knew that even just the two Fiocchi loaded rounds that the projectiles I was sending down range were dramatically different in external dimensions.


For your viewing pleasure

AE TMJ: .552" - They've revised the bullet on this in newer lots so it may be slightly longer
SS197SR: .688"
SS192/195/198: .815"
SS190: .835"

BTW factory rounds don't pull down very well in a kinetic bullet puller, had to get nasty with them. The SS197SR seems to have the softest lead compared to the AE TMJ.

 

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Buffman, thanks so much for posting this.

I have only shot the Fiocchi rounds:
Federal AE5728A, and
FNH SS197 SR.

I never knew that even just the two Fiocchi loaded rounds that the projectiles I was sending down range were dramatically different in external dimensions.
Knowing now that the AE5728A FMJ/TMJ projectile is approximately 0.136in shorter than the FNH SS197SR projectile, I now know why the AE round causes the problem in this thread (very first post, pic within):
http://fnforum.net/forums/fn-ps90/63049-ever-seen.html

The adhesive Fiocchi uses on the AE5728A projectile has approximately 0.136in less diameter area to grip the projectile onto the brass neck than the SS197 SR projectile.
As a result of less area to hold onto, the AE round is more prone to having the projectile break free in the neck and be pushed back into the brass.

Buffman, your guess that you posted in post #13 in thread I linked above is exactly why SS197 and other FNH offered rounds do not suffer the glue breaking loose in the AE5728A rounds:
The AE5728A projectile does not have sufficient surface area to mate with the brass neck to prevent a PS90 rifle from breaking the adhesive and pushing the projectile into the brass.

This additional 0.136in is also the reason why using a kinetic hammer to pull the SS197SR projectile is nearly impossible.
Hell, using a kinetic puller just to pull the AE5728A apart is hard enough.
 

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^^ I would concur with that assessment. Using the pliers it was very easy to break AE TMJ from the glue and remove it since the kinetic puller was taking FOREVER. AE TMJ bullet has been redesigned recently. Jay took down the picture of the re-designed AE TMJ, but I got a box coming that hopefully will have the new round to measure it.
 

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^^ I would concur with that assessment. Using the pliers it was very easy to break AE TMJ from the glue and remove it since the kinetic puller was taking FOREVER. AE TMJ bullet has been redesigned recently. Jay took down the picture of the re-designed AE TMJ, but I got a box coming that hopefully will have the new round to measure it.
I have two AE5728A FMJ/TMJ rounds I dismanteled.
The "older" AE5728A rounds were described as "TMJ" (I say "older" because I bought this box back in early January 2015)
The "newer" AE5728A rounds were described as "FMJ" (I say "newer" because I bought this box in late February 2015)

In the first pic below, these are both an FMJ and a TMJ side by side upright.

In the second pic below, this is an TMJ is on the left and the FMJ is on the right.
The TMJ has the core exposed at the base of this AE5728A projectile.
The FMJ is just that, fully metal jacketed, even the base covers the core.

Externally, their dims are the same.
Both projectiles are as advertised and within specs: 40gr

DSC_1112.JPG DSC_1113.JPG
 

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I have some of the first released AE and it's labeled as FMJ but the round is fully covered. The newest AE should have an open base. Jim do you have a picture?
 

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I have some of the first released AE and it's labeled as FMJ but the round is fully covered. The newest AE should have an open base. Jim do you have a picture?
Yeah, I edited my post to add pics.

I don't know if this has any bearing on which round is the newer and which is the older, but the lot numbers from which each round comes from as assigned by Federal AE are:
The FMJ round: Lot #0521469119
The TMJ round: Lot #0123469109

I do not know Federal's lot number convention and which lot is newer or older.
Also, I said "older" and "newer" based on when I bought each box of AE5728A.
I could be totally wrong because the box I bought later could have been on the selves for a very long time.
 

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What's the headstamp on the full encased, and on the open core?
The head stamp of the open core brass is: 5.7x28 FNB 13, I think. It's hard for me to see with these old eyes.
The head stamp of the fully enclosed core brass is the exact same: FNB 13
 

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hmm. The fully encased ones I have are FNB 12. :D
Interesting. Just to make sure my poor eyesight is not deceiving me, I took out a magnifying glass and both brass have FNB 13.

Maybe the FNB 12 stamped rounds might have different dims for the projectiles as compared to the ones stamped FNB13.

Busting out my cheap-o calipers, I measured my projectiles to be as follows:

Exposed core at the base:
Height (tip to base): 0.540in, which is 0.012in shorter than what you measured on yours.
Diameter: 0.221in, which is very close to the blueprinted 0.224in

Fully enclosed FMJ:
Height (tip to base): 0.550in, which is in spec to what you measured on yours.
Diameter: 0.220in, which is very close to the blueprinted 0.224in
 

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Jay pointed out that the NEW AE rounds are truly a jacketed projectile. The early AE rounds were plated, that would have a jacket covering everything. A jacketed projectile has lead exposed either at the front or rear.
 
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