I have tested some of the 77tmks in a tikka 8tw 223 and find them easy to load and not sensitive to seat depth (think they are tangent ogive), for me they are as easy to load for as the 77mk.
I believe the 30 cal tmks differ in that they are essentially a vld type bullet and are in no way similar to their mk brothers - attention to seating depth will give positive results.
This is a widespread issue with the 'new generation' of recently introduced bullets - raw BC has become the main objective these days, no doubt because that's what many shooters are basing purchase decisions on alone. Bullet form and 'temperament' has been forgotten or ignored by many.
At one time you knew that if you bought a Sierra MK it had an HPBT form with a relatively short nose section and a tangent ogive 7-9-calibres radius nose. Very easy to tune! There were a few exceptions - eg the 210gn 308 MK is a VLD type with a longer secant nose-form. Now though, Sierra's recent introductions have added a range of shapes ('forms') with no indicators as to whether they're tangent, secant, easy to tune or aggressive VLD types. (Berger by contrast groups the bullets by form under different names - BT (tangent); VLD; Hybrid.)
Hornady has to a certain extent done as per Sierra with its new ELDs. Although this manufacturer has primarily produced secant ogive types, the newer models appear to have moved to more 'aggressive' nose forms to reduce drag further.
77gn 224s and a few other comparable weights in the 73-77 range have usually been easy to tune / jump-tolerant forms as a primary use will be in magazine fed ARs in XTC or similar in rifles throated for 80s hence requiring large jumps for any 2.25/2.26 COAL loading.
One of the few ways now of knowing what you might be buying (other than user feedback on this and other forums which by definition has to be highly subjective) is Bryan Litz's
Ballistic Performance of Rifle Bullets book whose third edition evaluates around 950 models. The key factor is the Rt/R ratio which is a metric that allows some valuation of how abrupt the nose to shank junction is.
1.00 = true and full tangent. (tolerant)
0.50 = traditional VLD form as first used by Berger years ago (often finicky)
< 0.50 = a really aggressive front-end form.
The TMKs and ELDs now exhibit a variety of values in this metric using Bryan Litz's measurements in his book.
Taking the 224 and 308 TMKs that have been mentioned in this thread you get:
0.224
69gn ........... 1.00
77gn ........... 0.96
0.308
155 ............ 0.55
168 ............ 0.54
175 ............ 0.55
195 ............ 0.46
So Sierra has very sensibly (IMHO) stayed with tolerant tangent forms in the 22s and sacrificed BC for jump-tolerance for bullets to be used in magazine operation. Hornady has adopted an aggressive 0.48 Rt/R form in the 75gn ELD-M and Nosler has moved from 0.98 for its traditional 77 to 0.62 with the 70gn RDF, not a full VLD form but trending that way.
The 308 TMKs are a very different matter though as all four are now VLDs, Hence the people who've shot the still on the go 168, 175 etc traditional SMKs with their wonderfully tolerant tangent forms (168 = 0.90; 175 = 1.00) now saying ... "I can't get these new TMKs to shoot well for me with my old SMK loads."
There is no necessary consistency anymore - some TMKs have much less aggressive forms and are therefore pretty jump-tolerant. I use the 0.284 160gn TMK (Rt/R = 0.84) a lot and it is an easy bullet to 'tune'.
What did intrigue me a little with the adoption of synthetic tips in TMKs, RDFs, and ELD-Ms over HPBT types was the resulting increase in bullet OAL which all other things being equal sees the bullet having to be seated deeper in the case for magazine use. The 77 TMK is 0.070" longer than its SMK stablemate for a modest 4.66% BC improvement. With an already very deeply seated bullet at the 2.26" COAL magazine length any further reduction in case capacity for powder seems very undesirable to me in - in theory anyway as I don't shoot 223 in this type of rifle these days. .......... and of course, the TMK saw a price increase too justified by the 'improvements'.