Glensman Posted September 8, 2009 Report Share Posted September 8, 2009 Say for example a T3 in .243, how far would the zero move if you stuck on a T8 at 100 yards. That's just an example Quote Link to comment Share on other sites More sharing options...
Blackbart Posted September 8, 2009 Report Share Posted September 8, 2009 Don't know about 243 as i dont have one but i do know on my 22-250 at that range i would clean miss a fox if i had sights set for mod and then removed it to take the shot. Not very tech,but you get the idea. Quote Link to comment Share on other sites More sharing options...
Glensman Posted September 8, 2009 Author Report Share Posted September 8, 2009 Do you think would it affect the shot horizontally as well as vertically? Quote Link to comment Share on other sites More sharing options...
stevethevanman Posted September 8, 2009 Report Share Posted September 8, 2009 I have seen stuff on this on the net I think...I dont think it moves it more than 1"...but check your rifle really. I with rimfires, sometimes you get same point of impact but with centerfires it might be diffrent. Although this was ona 17HMR, the principal might travel accross. Steve Quote Link to comment Share on other sites More sharing options...
spider72 Posted September 8, 2009 Report Share Posted September 8, 2009 Blackbart doesn't say whether he would miss high or low? Moderators work by disrupting the gas pressure behind the bullet to bring it (the gas, not the bullet) below supersonic speeds.... inevitably this results in a small (ish) loss of energy in the bullet which would suggest a high miss with a rifle setup with a moderator? Sorry for the guessing I'm an engineer for a pharmaceutical company and spend my days around scientists it must be rubbing off.... damn... Quote Link to comment Share on other sites More sharing options...
Blackbart Posted September 8, 2009 Report Share Posted September 8, 2009 Do you think would it affect the shot horizontally as well as vertically? It did on mine,cant remember exactly but it was something like 1 inch high and 3 inches right @120 yards,so it does move quite a bit Quote Link to comment Share on other sites More sharing options...
magman Posted September 8, 2009 Report Share Posted September 8, 2009 Think of a barrel doing a figure 8 So it could be high, low , left or right Quote Link to comment Share on other sites More sharing options...
spider72 Posted September 8, 2009 Report Share Posted September 8, 2009 I was thinking of a clamped rifle for zeroing... 3 inches to the right is a long way out at 120 yards, what range was the rifle set up at? which direction is the rifling (viewed from the breech)? Bloody scientists got me asking for more data..... Quote Link to comment Share on other sites More sharing options...
Billy. Posted September 8, 2009 Report Share Posted September 8, 2009 My .270 will be thrown off by a mile if I so much as move it by a quarter turn... However my .22LR bolt action will keep its zero if I take it off...! Madness Quote Link to comment Share on other sites More sharing options...
Blackbart Posted September 8, 2009 Report Share Posted September 8, 2009 I was thinking of a clamped rifle for zeroing... 3 inches to the right is a long way out at 120 yards, what range was the rifle set up at? which direction is the rifling (viewed from the breech)? Bloody scientists got me asking for more data..... Can't remember exact zero set but would have been about 160-180.The rifling is right hand twist(i think)1-12 twist rate Quote Link to comment Share on other sites More sharing options...
Baldrick Posted September 8, 2009 Report Share Posted September 8, 2009 (edited) The POI from my old .243 T3 would move 3" high and 4" to the left (at 100 yards) when the T8 moderator was removed. Every barrel and mod combination will produce different harmonics - only trial and error works as a means of forecasting POI shift. And don't clamp any rifle when zeroing, ever. Zero the rifle in the manner which you would shoot it in normal day-to-day use. Edited September 8, 2009 by Baldrick Quote Link to comment Share on other sites More sharing options...
Mungler Posted September 8, 2009 Report Share Posted September 8, 2009 My .270 will be thrown off by a mile if I so much as move it by a quarter turn... However my .22LR bolt action will keep its zero if I take it off...! Madness Ditto. Some rifle = loads, some very little. Suck and see. Quote Link to comment Share on other sites More sharing options...
spider72 Posted September 8, 2009 Report Share Posted September 8, 2009 And don't clamp any rifle when zeroing, ever. Zero the rifle in the manner which you would shoot it in normal day-to-day use. I never clamp a rifle for zeroing.. I was looking at it with a view of the least variables. I zero my rifle as i would use it i.e. off the sling, off sticks or prone. but to experiment i might clamp it to see the difference with ammunition etc.. from a fixed point.. Quote Link to comment Share on other sites More sharing options...
Glensman Posted September 8, 2009 Author Report Share Posted September 8, 2009 Yeah I was just wonderin did it move a serious amount, and now I know that it does! Quote Link to comment Share on other sites More sharing options...
maddog546 Posted September 9, 2009 Report Share Posted September 9, 2009 I'm with you harfordwmj on the .270 change of zero,It has brought my Remy 700 to full travel on the vertical plane of the scope to zero it,cant believe the difference it made,whereas the .223 only moved an inch or so. Quote Link to comment Share on other sites More sharing options...
Dunkield Posted September 9, 2009 Report Share Posted September 9, 2009 I don't know there is any hard and fast rules, but when my CZ had the full length barrel and the PES mod fitted it shifted my POI 13 clicks low and 5 left from memory. The guy who threaded the barrel predicted that almost exactly, so there must be a rough rule of thumb. I would guess, but I don't know for sure, that shorter and/or stiffer barrels would be affected less, the shift is much less now I have a chopped barrel and have a lighter/smaller mod. That's a .223 BTW. Quote Link to comment Share on other sites More sharing options...
TheHunter Posted September 10, 2009 Report Share Posted September 10, 2009 (edited) I agree with StuartP There can't be any logical hard and fast rules as to where an MPI would be with and without a mod fitted. I am sure it could be done "per rifle" but as a general rule, No. For example a heavy barrelled .308 would bend less if it had a .5Kg mod added compared to a flute barrelled .223 Half hour on the range should give you a rough idea to the adjustment required after fitting or removing your mod. Edited September 10, 2009 by TheHunter Quote Link to comment Share on other sites More sharing options...
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