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What is the elevation (above sea level) and the approximate temperature where you were getting 4-5 inch groups? Was it windy? What roughly were the shape of the groups?
Strung vertically? Strung horizonatally? random? Single flyers?
This is where a chrongraph would be handy.
Cold can give higher air density and reduce stabilty (unlikely this time of year but your profile doesn't show where you live).
High temperature can give higher chamber pressure and velocity driving the bullets into the transonic region causing instabilty and (usuallly) random point of impact errors which may increase more or less than linearly with distance. .
Launch angle error will generally be linear with distance (like a loose scope mount).
Wind will typically give horizontal stringing more than linear but not with the square of the distance.
Velocity variation will usually cause vertical stringing with the square of the distance.
Some people keep targets with small groups. All those tell you is that you're doing everything right. A useful test target will have 5 to 10 shots each marked with the time it was shot and its chrongraphed velocity. Also record the gun, cartridge, bullet model, elevation, temperature, and air density (or barometric pressure and humidty). Those are worth keeping.
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