Here are some guidelines that apply to using a 22 to train for F-TR (308 Winchester loads) midrange (e.g. 600 yards) and long range (e.g. 1000 yards) competitions. Of course they may apply in other situations but since I shoot F-TR and do use the 22 for training, I will cover the types of beliefs that come from conversations during matches (and from competitors far better than I). Few shooters have the luxury of closely matching trainer and competition firearms and do not need to do so to improve skills. Most of the rest of what is said here is necessary thought.
Shoot the same position with 22 as you do at longer ranges with center fire ammunition. For F-TR this means prone with front bipod and rear bag with ears. Put together and use a 22 that has the same stock and brand of trigger with the same ounce or pound pull as the longer range rifle. Practicing bench rest at 100 yards is not the most efficient way to prepare to shoot 600 yard F-Class in competitions.
The point of impact of each round must be visible prior to making a decision about the next shot for the training with a 22 to be useful. This is a limitation for which there is no workaround. This is a absolute necessity.
At 100 yards, the primary purpose of training is called “putting in trigger time”. It is used to develop core skills of breath control, sight picture and trigger pull (squeeze). It doesn’t particularly help with either wind or mirage skills (unless you are already a X or 10 ring only shooter!). There should be no problem seeing the impact location of each round fired at this distance.
At 200 yards the impact hole should be visible with the scope on the rifle or by using a spotting scope. Because rounds in the black may not be visible, I use targets that have only the scoring rings indicated by a black line so I can see the impact locations in white areas of the target. The following picture (shot for group under no wind early morning sight in conditions) shows this modification:
Two hundred yards is a excellent distance for learning to read wind and mirage. Most shooters opine that for training it is analogous to 800 to 1000 yard high power shooting. If trigger skills are already there, give priority to training at this distance and learning to read wind and mirage and to get that immediate feedback on each shot so you can see how you did with reading conditions and making a decision about where to hold.
At 300 yards the primary problem is seeing the point of impact of the 22. A little mirage can hide the hole. Increasing the power of even high quality spotting scopes can degrade the image to the point the hole can’t be seen. It’s fun to shoot at 300 yards but as a training distance for 1000 yard competitions it has these serious limitations and is not as useful as 200 yards. Since a match has 20 rounds for score with 20 minutes for completion, training should be then with 20 round segments over 20 minutes. It would be rare for perfect visual conditions to last long enough to fire 20 rounds!
I spend approximately equal time at 100 and 200 yard distances.
Hope these guidelines help.