Help with bullet ID. 2155 vs 2156

[Adam0321/0306]

So I purchased these from a member a couple of years ago and am just now getting around to using them as my stock of 2155s are drying up. The box says they are 2155s, but I am pretty sure they are 2156s as they are longer.

The “2155s” on the left are the ones I bought from this forum.

They measure
OAL 2.002
Base to O-give 1.550

The ones on the right I purchased from midway.
OAL 1.140
Base to O-give 1.565


thoughts? I know they will work in my 308, just noticed a difference when I grabbed them.

 

[10XSHOOTER]

The 2156 should weigh 155.5grs The 2155's are 155.0 grs

 

[clowdis]

The 2156 is 1.205 oal and weighs 155 grns. So I think you have 2155's and 2156's.

 

[Ned Ludd]

Normal Lot-to-Lot differences could make any interpetation very difficult. Call Sierra, they may be able to help you out.

 

[Mikey_P]

The 2156 is 1.205 oal and weighs 155 grns. So I think you have 2155's and 2156's.

Agree with @clowdis. In looking at the dimensions given in Bryan Litz's book on Applied Ballistics, the OAL for the 2155 is shown as 1.131" and the 2156 is 1.210" OAL. So, it does look as though you have some of each.

Mike

 

[Bulletman]

Both bullets weigh 155 grains neither are 155.5 grains, There is an ogive and a closed nose difference which results in the 2156's being longer. Zooming in on your second picture, the left bullet is a 2156 and the right is a 2155.

 

[Adam0321/0306]

Ok, sorry to revive this thread. But the picture shows what I know are 2155s and what I know are 2156s. Then there are the bullets that were in the 2155c box. Which not not match the 2155 or the 2156s. Is this just a simple variation in lots?

 

[Hengehold]

I measured three samples of both bullet types. My measurements are below. Notice there is a .016” difference in BTO between the two different models.

In my opinion, the dead giveaway of a difference between 2155 and 2156 is the obvious longer OAL. I would forget about the BTO and just measure the OAL.

#2156:
OAL
1.212”
1.215”
1.217”

BTO
1.462
1.463
1.463

#2155:
OAL
1.127
1.127
1.131

BTO
1.478
1.479
1.479