I have a pre-64 70 parts rifle with an after market barrel and parts from different early model 70’s and an ugly stock, it wears a Weaver 2 1/2 post scope.
I decided to try to work with 225 grain bullets and this is the results so far.
Using the same load of TAC, Hornady brass, 9 1/2 primers.
225 grain Sierra - several groups ~ 1 MOA or less
225 Nosler Ballistic Tip one group less than 1/2 MOA
225 Nosler Partition one group almost 4 MOA
I found this strange as usually, my testing, partitions are one of the most accurate bullets.
Anyone use 225 grain ballistic tips on game?
A couple different problems I see is you are using the "same load of TAC", according to your post. Keep in mind you are going to have to work up a load. You can't expect the same charge weight to work the same for every bullet, even though they are the same weight. The next thing wrong is you are basing your findings on 1 group for each bullet (ballistic tip and partition). You have no empirical evidence, as there has been no load work up done and 1 group of each does not tell you anything. Do yourself a favor and try RL15, but work up a load properly this time. If your rifle is worth anything, it will shoot a partition into 1 moa (for 5 shots) with proper load work up, components and procedures..
