I was going by this, taken from
Knowledgebase
Suggested loads: .243 Winchester Barrel length: 22”
No ID Sectional Density Ballistic Coefficient Observed MV Fps ME
Ft-lb’s
1 FL Hornady 100gr BTSP .242 .405 2890 1854
2 FL Hornady 95gr SST SF .230 .355 3115 2047
3 FL Winchester55gr BST .133 .276 3840 1800
4 FL Winchester95gr BST .230 .379 3020 1923
5 FL Federal 85gr GK HPBT .206 .293 3220 1956
6 FL Federal 85gr TSX .206 .333 3130 1849
7 FL Remington 90gr Scirocco .218 .365 3050 1858
8 HL 85gr Partition/GK/TSX .206 .315 (Av) 3200 1932
9 HL 95gr SST or Nosler BT .230 .355 3050 1962
10 HL 100gr Partition .242 .384 3000 1998
11 HL 105gr A-Max .254 .500 2950 2029
No At yards 10mphXwind Velocity Ft-lb’s
1 300 8 2200 1075
2 300 7.8 2343 1158
3 300 8 2713 899
4 300 7.3 2331 1146
5 300 9.5 2284 985
6 300 9 2253 958
7 300 8 2307 1064
8 300 8.5 2323 819
9 300 8 2288 1104
10 300 7.5 2300 1173
11 300 5.4 2436 1383
And .22-250:
Suggested loads: .22-250 Barrel length: 24”
No ID Sectional Density Ballistic Coefficient Observed MV Fps ME
Ft-lb’s
1 FL 55gr Remington SP .157 .197 3650 1627
2 FL 55gr Hornady V-Max .157 .255 3650 1627
3 FL 55gr Federal TBBC .157 .201 3600 1583
4 FL 60gr Federal Partition .171 .228 3550 1680
5 HL 53gr Barnes TSX .151 .231 3650 1567
6 HL 55gr FMJ .157 .272 3650 1627
No At yards 10mphXwind Velocity Ft-lb’s
1 300 13 2200 590
2 300 9.3 2490 756
3 300 12.6 2187 584
4 300 11 2295 702
5 300 10.5 2384 669
6 300 9 2506 767
I'm unsure which of the .22-250 bullets listed offers the best comparison to the .243 bullet highlighted, so I haven't highlighted a .22-250 option. But there appears to be a small but worthwhile advantage for the .243 over the .22-250. Bear in mind also that these figures are taken from a .243 with a 22" barrel. Mine would be 24". And the Sako Varmint has a 1:10 twist so it will handle heavier bullets as well if required
There ain't a lot in it but this is why I chose the .243 as a 55 grn vermin round over the .22-250.
There is no perfect round for anything. You have to make a decision based on something. Hope I've made the right choice. Time will tell.