Range Report New Sierra 7mm 180gr SMK

[Jeffvn]

Re: New Sierra 7mm 180gr SMK

I have to join the crowd on this one, my KMW 7WSM with a 9 twist Kreiger barrel hated the Hornady 162s, but hammers with the Sierra heavies, the Berger 180s, the JLK 180s, and the Cauterucio 189s. I will try the Matrix 190s also, but have every expectation that it will shoot them just fine.

If your like them shoot them, they perform well and are very cost effective no doubt.

JeffVN

 

[James in Wyoming]

Re: New Sierra 7mm 180gr SMK

Any further range reports on this bullet? I have found them quite satisfactory in 9 twist Bartlein .284. With RL-17, WWbrass, and both Wolf and CCI BR2s, I'm getting excellent accuracy, good sd numbers and just under 2900 from 27" barrel. I am loading to mag length of 2.950 so the Bergers, while they shoot well, have to be single-loaded. The 180 smk performs better for me than the 175 and seems very promising but have not shot it much as distance yet.
Best,
James

 

[RobG]

Re: New Sierra 7mm 180gr SMK

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: James in Wyoming</div><div class="ubbcode-body">Any further range reports on this bullet? I have found them quite satisfactory in 9 twist Bartlein .284. With RL-17, WWbrass, and both Wolf and CCI BR2s, I'm getting excellent accuracy, good sd numbers and just under 2900 from 27" barrel. I am loading to mag length of 2.950 so the Bergers, while they shoot well, have to be single-loaded. The 180 smk performs better for me than the 175 and seems very promising but have not shot it much as distance yet.
Best,
James </div></div>

Is this a .284 Win? Is that speed typical for that heavy a bullet? I ask because out of a 7mm RM I get 2930 using 63g of R22, Rem brass, and Fed 215 with a 26" Krieger.

 

[James in Wyoming]

Re: New Sierra 7mm 180gr SMK

Yes, .284 Winchester. Don't know about typical but F class shooters with the .284 and variations go significantly faster. I was hoping to be able to get good accuracy with these in the vicinity of 2900, with the limitations of mag length and 27" barrel, so I'm quite satisfied with the outcome.
Best,
James

 

[mattmcg]

Re: New Sierra 7mm 180gr SMK

Bump this thread for more info on the Sierra 180gr 7mm Matchking. There seems to be quite a bit of bullets hitting the market over the past 6 months so would love to hear feedback from folks shooting these at longer distances.

 

[mattmcg]

Re: New Sierra 7mm 180gr SMK

I received a box of 100 of these bullets a week ago and decided to take a few measurements before and after pointing. I also took a few measurements to the Ogive using a Davidson comparator. Thought this information might be helpful for a few of you either shooting or considering shooting these bullets

Unpointed---Pointed---Length to Ogive
1.4570---1.4630----.7790
1.4565---1.4635----.7795
1.4585---1.4640----.7775
1.4620---1.4665----.7810
1.4625---1.4665----.7805
1.4545---1.4595----.7795
1.4530---1.4575----.7795
1.4625---1.4685----.7805
1.4535---1.4615----.7805
1.4595---1.4645----.7810
1.4605---1.4665----.7780
1.4575---1.4640----.7810

Averages for 12 bullet sample:
1.4581---1.4638----.7798

*Bullets pointed with Whidden pointing die and #0 insert.

A couple of conclusions. The stated length from Sierra of 1.455" is a little shorter than what I saw with the sample. I was impressed with the minimal standard deviation on the LTO. If the BC is accurate as claimed, this should be an excellent bullet for the 7 SAUM in a short action fed by a detachable mag.

I receive a box of the Berger 180gr Hybrids next week and will run through the same exercise. My thought is that while the BC may be a tad higher, it will come at the expense of a reduced powder charge given the longer length taking up precious powder capacity. Will post more next week when I know more....

 

[jbailey]

Re: New Sierra 7mm 180gr SMK

Yes, good analysis Matt-
Please keep us updated on your analysis. I have a 7SAUM on a short action in works right now and my plan was to try the Berger 180 Hybrid first and then go to the 175 SMK, but I'm interested by your work on the 180 SMK.
thanks

 

[jbailey]

Re: New Sierra 7mm 180gr SMK

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hill billy</div><div class="ubbcode-body">I noticed today while loading the last of my 175's and a few 180's that the bearing surface on the 180's is much longer. It' s barely perceptible, but there is an obvious shoulder on the 180's as it transitions to the flat. The 175's are a much smoother transition. I wonder what effect this has on BC. </div></div>

This is caused by the fact that the 175gr has a tangent ogive profile while their new 180gr has a secant profile. This could cause more seating depth issues for the 180gr SMK than the 175gr, which, if that is the case, I don't have the patience to screw with the 180gr. The whole idea behind Berger's Hybrid is to change the ogive profile such that it has less drag like the secant profile and at the bearing surface junction have a tangent profile, i.e. best of both worlds - lower drag and lower seating depth sensitivity.

 

[mattmcg]

Re: New Sierra 7mm 180gr SMK

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JamesBailey</div><div class="ubbcode-body">
This is caused by the fact that the 175gr has a tangent ogive profile while their new 180gr has a secant profile. This could cause more seating depth issues for the 180gr SMK than the 175gr, which, if that is the case, I don't have the patience to screw with the 180gr. The whole idea behind Berger's Hybrid is to change the ogive profile such that it has less drag like the secant profile and at the bearing surface junction have a tangent profile, i.e. best of both worlds - lower drag and lower seating depth sensitivity.
</div></div>

Has anybody determined the Rt/R on the Sierra 180gr? I'm wondering how much more secantial it is that the 175gr.

I really wish that the industry would give us more information about these bullets. Spec sheets with dimensional and ballistic data should become standard practice (including G1 and G7 BCs).

 

[jbailey]

Re: New Sierra 7mm 180gr SMK

You might contact Sierra. I know that the 180gr is secant because I remember reading it in their marketing materials describing the bullet. Or maybe Bryan Litz will do it in his 3d edition