Hello all...i am new to the site and new to gsp's. my pup is 4 months old and he is 18" and about 27#.  His Sire is 27" and 74# i believe and Dam 23" and 55#....he was under weight when I got him at 8 weeks...he had a terrible worm problem and only weighed about 6 lbs... since then he slowly grew to about 13lbs at 3 months and now at 4 months 27  seems to be really sprouting up...but i do see alot of different dogs seeming to be alot bigger at this age?...not really worried about it as he is doing amazing with his training...points birds better and holds longer than my friends 7 month old weimeriner..sp?.....all around best dog ever could have asked for...just wondering if there is any general rule or something to guesstimate my pups size at maturity....thank you all!!