G'day Rod
in regard to our original idea to introduce and trial 300m rimfire BR, after extensive testing this year, it now seems that once the discriminatory nsw BR bans are lifted it is most likely that we will limit our proposed rimfire BR matches to 200 (metres or yards).
no doubt some of us will still shoot 300m, but the factors that have led the reduction from 300 to 200 are related to the fact that most shooters of ours are not able to set their rifles up for the longer distance.
in actual measurements and depending on the ammunition used to obtain a 22rimfire point of aim trajectory for 300metres the scope and mounts need to be able to provide more than 50 to 60 to 70 minutes of vertical adjustment.
although it depends on the ammo used, at 100yards we measured the impacts being between 55 and 65 inches high when sighted in for 300metres.
as most of our potential shooters wish to use their standard hunting 22s, for them to adapt for 300metres would mean additional expense for tapered bases, and or insert mounts and or a more suitable scope with greater vertical travel.
for 200 yards around 20 to 30 inches of adjustment are needed and it is much easier to achieve this with their regular scopes and mounts.
although the wind allowances at 200 are substantial, i suggest that if people move to 300m they will find the wind effects much more noticeable and soul destroying.
others can do as they please, but our aim is to encourage participation, enjoyable and satisfying rimfire LRBR.
for my testing at 300m and beyond i used my howa m100 with 25min bases, burris rings with 40 moa inserts and tasco sniper scope which has +- 50 minutes of vertical adjustment.
typical group results at 300 are as follows
sks yellow standard (good batch)
sks yellow std (not so good batch)
sks target went reasonable
sks subsonic and norma target - note poa for norma was lower red circle.
by the way,in all of this testing at 300m, due to the mirage and existing light conditions all shooting was done blind.
the only indication of hitting the plates was sometimes the "ping of hitting the plate" could be heard.
no doubt on other ranges, depending on the existing optical conditions it would be possible to see bullet impacts on paper or steel plates etc. at 300m.
on the same days as the 300m testing, in the same conditions , in testing at 200m it was possible to see the impact positions on the plates.
if anyone else is into the challenge of rimfire LRBR, please feel free to share your experiences and findings.
cheers
dave g
