Uneven seating depths and OAL's with .38 sp +P Win Ranger T 130gr Bonded JHP

[Moonshot]

QC issues affecting seating depth aside, I am most concerned and curious about the huge variance in velocity with the GDs in the 442 vs the DS.

Unless it's a typo, an almost 100 fps increase with 1/8" more barrel doesn't make sense to me, unless there is a significant difference somewhere else. I don't reload, so I don't know if this could be caused by a variance in BCG, in-spec variation in ammo charge, or bullet seating depth, but this velocity swing is the red flag I take from this, especially when the Ranger velocity spread from both guns was essentially zero.

Throw in the 2" K-frame and I am really confused. Can multiple platforms with essentially the same barrel length show that much variation in velocity, or is there something else at work here?

[Beat Trash]

QC issues affecting seating depth aside, I am most concerned and curious about the huge variance in velocity with the GDs in the 442 vs the DS.

Unless it's a typo, an almost 100 fps increase with 1/8" more barrel doesn't make sense to me, unless there is a significant difference somewhere else. I don't reload, so I don't know if this could be caused by a variance in BCG, in-spec variation in ammo charge, or bullet seating depth, but this velocity swing is the red flag I take from this, especially when the Ranger velocity spread from both guns was essentially zero.

Throw in the 2" K-frame and I am really confused. Can multiple platforms with essentially the same barrel length show that much variation in velocity, or is there something else at work here?

Yes. I would want to measure the BCG of each gun and compare these measurements to the recorded velocities. That could end up explaining the variation.

[Moonshot]

Yes. I would want to measure the BCG of each gun and compare these measurements to the recorded velocities. That could end up explaining the variation.

A variance in the BCG between the DS and the M&P (with the M&P having the smaller gap) would explain the velocity difference between the DS and the M&P, as both brands of ammo showed a similar increase in velocity going from the DS to the M&P, but I don't see how BCG alone would explain the velocity variance between the 442 and the DS, as the Ranger ammo showed virtually no difference in velocity between these two platforms. Wouldn't a difference in BCG between the 442 and the DS have affected both brands of ammo more or less equally?

[deputyG23]

Yes. I would want to measure the BCG of each gun and compare these measurements to the recorded velocities. That could end up explaining the variation.

As soon as I can find a set of feeler gauges in my messy shop, I will measure BCG and report back.

[blues]

Just came across this thread. I have 10 boxes with the same lot number markings as in the OP. Purchased from SGAmmo.com back in late June 2016. Have not fired any of this ammo.

I'd be very interested in hearing of any further info / data regarding these rounds.

Purchased for use in a 3" 686+ and a 642-1.

[blues]

Couldn't edit the above post...

Just pulled three boxes of the 10 I have on hand and pulled a number of rounds from each. I'm not seeing anything that appears troubling.

There was the occasional small bit of variation between rounds in terms of the position of the cannelure relative to the case but it was of even and symmetrical height around the circumference in each instance.

[deputyG23]

As soon as I can find a set of feeler gauges in my messy shop, I will measure BCG and report back.

Found the feeler gauges.
442-2 BCG .005
Colt DS .006
S&W M&P less than .002
S&W 64 .004.

[Moonshot]

Found the feeler gauges.
442-2 BCG .005
Colt DS .006
S&W M&P less than .002
S&W 64 .004.

What does this tell us? I don't mean this as a smart ass question, I really want to know.

Negating the 4" M64 for a moment and sticking with only 2" barrels, the DS has a BCG 3 x larger than the M&P, yet the velocity loss from the DS vs the M&P with both brands of ammo is relatively small. On the other hand, the 442 has a BCG smaller than the DS, yet there was significant velocity loss in the 442 with the Gold Dots, less so with the Rangers.