Help.TC Impact wont group

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fredbear92

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Hello everyone.Im trying to shoot Barnes MZ 300 gr out of my Impact.They aren't grouping at all.The first shot loaded(clean bore)seems to be within an 1" or 2" of bullseye.The shot is producing 1 round hole.Loading the 2nd shot(not cleaned in between)produces impact 7"-8" left and 2"-3" lower than the first shot.Same sight in point.Also the bullet hole seems to be keyholing.Definately not round.In the Barnes MZ literature,the 300 gr are needing 1-26" twist or faster.The Impact is a 1-28".I tried lots of 2 shot groups like above cleaning between each 2 shot group.Same results.The 1st shot was always a significant distance closer to impact than the 2nd.Just for grins.I tried some 310gr lead Knight bullets.Yes I weighed these before firing.With the 310 gr I could fire 3 shots(no cleaning between)back to back and impact was producing 3" groups.Im thinking the extra length of the Barnes copper bullet aren't stabilizing.Because it definately seems the like the shorter lead bullet.I loved the 300MZ in my old TC Black Diamond but not so in the Impact.Without cutting the 300MZ to a shorter length or throwing them away(ouch),does anyone have any ideas?Might be needing to trade around 100 qty of the 300 MZ if anyone is interested. All testing was done at around 50 yards.
 
What kind of and how much powder are you loading under these bullets? Inlines can really throw me. I have one that one day will shoot perfect and the next time out, spray all over. I usually blame myself. I really have no idea why it is doing this to you. You sound like an experienced shooter to me.
 
I know I read a post from someone that shoots the 290 Tmz out of an Impact with great accuracy. I don't think they used the supplied sabot however. There are lots of possibilities to try. If the mz's don't work advertise in classified.
 
Im shooting 2-50gr pellets of Triple 7 powder.Ignited by Winchester Triple 7 209 primers.Ive checked my rings and bases and all are tight.Known good Weaver scope.Im shooting on a 35 degree day and using a lead sled for the rest.I just cant figure out why the first shot acts as it does.The second shot may be fouling induced???First shot is usually a circular hole,and the second shot is always a hole with a slight tear to the right side of bullet impact.Ive switched sabots that came with the factory barnes bullets.Way too tight in my bore.Ive shot crush ribs,and hph 24.I believe the factory Barnes sabot is an hph 12.No change to above scenario.The mmp 3 petal ez sabots were too loose when loading to feel confident.Im at a loss.This is a first for me.I thought the key here was the 300 grain weight.But the 310 grainers shoot so well.So the weight cant be an issue.The only possible factor remaining is bullet length.The bare bullets measure 1.043" for the Barnes 300gr,and 0.792" for the 310 grain Knight pure lead.The assembled sabot/bullet combo measures 1.340" for the Barnes,of which 0.351" exposed above petals.The assembled sabot/bullet combo for the 310 gr is 1.105".Of which 0.130" remain above petals.These were Knight part # 900-201,but I can no longer find this part # on the internet.Sometimes I guess you just gotta step back and punt.Thanks for the help.
 
To possibly eliminate the keyhole on the second shot, try knurling your bullets between two files. This may help the bullet grip the sabot.

Is that a flat based bullet? If so, maybe try a Harvester smooth black sabot.

Does the barrel wiggle side to side with the action closed?

My son's Impact hunting load is 90gr of BH209, 250gr Barnes TEZ with a Harvester smooth black sabot, Fed209 primer. The rifle does shoot a little better after I shimmed the the barrel to eliminate the barrel wiggle, I also free floated the forearm.
 
Yes these are flat based bullets.I cannot differentiate any movement concerning the hinge pin.If there is ,it will be thousands of an inch.Im starting to think that the 777 pellets are leaving enough fouling behind that Im not getting the same depth when seating each bullet.When I cleaned the Impact that night,I noticed a "crud" ring in about the general area that the base of the sabot ought to be.So Ive ordered some Blackhorn 209 powder.Ive also ordered some Barnes MZ 250 grains as well as a box of Hornady XTP's.Hopefully between different powder and shorter bullets I can figure this one out.Thanks.Ill post back whenever I get a chance to shoot again.
 
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