Pointed 80gr SMK BC

[Quickoz]

G'Day all,

Just wondering if anyone has tested the new pointed 80gr SMKs and what if any is the BC improvement. Im using the un pointed ones but want to know the improvement when I do get some of the new ones.

Cheers.

 

[XBBR Shooter]

Sierra lists them both with a BC of 0.420.

 

[Snuggie]

I was pointing the "unpointed" ones and got great results. The box of new ones pointed from the factory showed lots of them that the hollow point was closed too much. This degrades BC. Not as good results. Went back to pointing my own. Hope that shines a little light in it.

 

[jr600yd]

I can not give you test results only my observations on pointing my 80 grain SMK's. Out to 500 yds I really didn't notice much change. 600 yds pointed Bullets held tighter verticle. With an improvement around 3%. At 1K groups showed up tighter with improvement in both verticle and horizontal about 5% when I did my part.

 

[Snuggie]

My X-count went up when I started pointing my 80 SMK's. Shooting F/TR at 600.

 

[Twitchy]

jr600yd-were your results with the factory pointed or your own pointed?

I just got a new shipment of 80 SMKs to load up and noticed they are now pointed like the 90s. My last batch of 80s was not pointed.

 

[Berger.Fan222]

Using the LabRadar leads to the following:

(Factory) Pointed G1 BC: 0.490 G7 BC: 0.245

Unpointed G1 BC: 0.430 G7 BC: 0.215

 

[jr600yd]

My observations were based on non-pointed factory Bullets. I pointed them myself using a Whidden bullet pointing die.

 

[sparker]

Using the LabRadar leads to the following:

(Factory) Pointed G1 BC: 0.490 G7 BC: 0.245

Unpointed G1 BC: 0.430 G7 BC: 0.215

Hi, Would you mind posting the raw data and conditions here? That BC jump is very interesting.

Scott Parker

 

[Ned Ludd]

The numbers Berger.Fan222 posted represent about a 14% increase in BC. Although smaller caliber bullets are reputed to sometimes benefit from pointing more than larger caliber bullets because the meplat diameter can be a larger fraction of the caliber, that seems like a really large jump. Based on fairly crude drop measurements, I roughly estimate I'm getting somewhere in the 4-5% BC increase range by pointing Berger 80.5s and 90 VLDs. Therefore, I would be cautious about interpreting BCs determined using the LabRadar for several reasons. The first is that there can be significant variation even within a given lot, not to mention variation between lots. So the sample size need to be sufficient to apply the information to a particular bullet in a general way. Second, the manufacturers of the LabRadar do not recommend using it for this purpose as described in another current thread:

http://forum.accurateshooter.com/th...th-labradar-velocities.3906224/#post-36802265

Certainly nothing wrong with generating the numbers, I would do it myself if I owned the unit. However, I would be fairly conservative with regard to how much emphasis I placed on BC values generated by this approach.

 

[Berger.Fan222]

Hey, if anyone else has measured BCs for the pointed SMKs, I'm certainly all ears.

The BC of the 90 SMK jumped considerably when Sierra remeasured it after they started pointing, and I would definitely defer to the experts at Sierra rather than place too much confidence in numbers determined from one lot of bullets with the LabRadar.

But for now, the LabRadar numbers are all I have, and I would tend to believe them more than guesses based on observations of other bullets and especially more than inferences based on drop observations.

 

[Berger.Fan222]

I asked around and a friend forwarded an email from Sierra.

Sierra has measured the BC of the pointed 80 SMK to be 0.461 in the highest velocity band. This is a 10% improvement over their measured value of 0.420 for the non-pointed version.

 

[LVLAaron]

(Factory) Pointed G1 BC: 0.490 G7 BC: 0.245

Sorry to bring up an old thread but the G7 of .245 seems to be almost exact for me as well.