Some of the TMKs are tolerant largely tangent ogive designs, not exactly as per old fashioned SMKs with 7 or 8-radius ogive nose sections and on or near 1.0 Rt/R junction ratio values, but as per more recent long-range tangent designs like Berger's LRBT models. I shoot the 7mm 160 gn TMK a lot and it's a very tolerant easy to tune model.
However, other TMKs are much more like VLDs or maybe Hybrids and only seem to shoot well with large jumps. As far as I can see all 30-cal TMKs are VLDs or 'VLD-ish'. Exactly the same applies to many of the new pointed models. The problem is that there is no across the range consistency and unless you invest in
https://store.appliedballisticsllc.com/Ballistic_Performance_of_Rifle_Bullets_3rd_Edition_p/0010.htm
you simply don't know unless you can get information on this forum or other such source, from somebody you know who has tried them, or by contacting Sierra's tech helpline.
Many of the new-model pointed bullets are what I'd call uber-VLDs with very long secant nose sections at around 28-calibre radius and Rt/R values well below the 0.50 mark that signifies an original type VLD 'form' as designed by Bill Davis for US military 300M ISSF team use back in the in the 80s and made by Walt Berger. The new 110gn 6mm and 183gn 7mm SMKs which are of identical design, but 'scaled' to calibre fall into this category. I assume the new 200 and 230gn SMKs
http://bulletin.accurateshooter.com...ierra-matchkings-in-223-264-and-308-calibers/
fall into this category too looking at the pictures and also based on some data about the 200gn model on another thread in this forum. I wouldn't be surprised to learn that the 230 is the same 'form' as the 110 six and 183 seven simply scaled up to 308 diameter.
Some other existing older SMKs now being produced in 'pointed' form are identical to their predecessors, the smaller meplat aside ..... but compare drawings and dimensions in Bryan's book and you find some others have had modest but still significant changes made to their nose lengths and shapes. So simply loading a new-version pointed SMK as per its traditional predecessor as you have for years may or may not work. This wopn't be helped either by both original and modified forms being on shop shelves or classified ads too for years to come. (This distinction applies of course to the original pointed model, the second generation 0.308 155gn Palma MK #2156 which is a very different shape from its still in production older brother the 2155 and saw a considerable learning curve needed among fullbore and Palma shooters to make it work optimally.)
I certainly don't want to sound like I'm knocking Sierra, a company whose products I've used for around 40 years and always liked. In fact, I'm really pleased that Sierra has uprated its MK range and introduced so many good new models. Its quality control has improved enormously too as far as I can tell through checking weights and BTO consistency. I only wish that it would group its bullets into differently named categories as Berger does with VLD, BT, BTLR, and Hybrid, or at the least provide more information on its literature. As far as I'm concerned, the antediluvian 168gn 7mm MK and new 183gn MK are such dissimilar designs they should be differentiated in their branding and the latter also provided with advice (as Berger does on tuning COALs for VLDs and Hybrids). The former is completely jump tolerant; the latter needs IME a very large jump indeed to make it group.
I suspect this also applies to the 6mm 110, and 308 200/230 models. It does the customer no favours at all, or Sierra's sales either in the long run if an inexperienced buyer trades up to one of these uber-VLD 28 cal nose radius models and then can't get it to shoot or wastes most of the first box and a slice of expensive barrel life in experimentation. There is more to necessary technical advice than recommended twist rates - which Sierra is very good at giving even if half of AS Forum members then argue about them and tell others to ignore the advice (!!) - to making many modern bullets perform well.
