My puzzling 6XC experience..

K

Kirk Ethridge

New member
My puzzling 6.5XC experience..

I decided to build myself a 600 yd rifle..& since i had nothing in my collection in 6.5mm I decided to build a 6.5xc (to avoid the barrel burning reputation of the 6.5-284 and to be able to use dies i already had..(6xc) just by changing the neck/shoulder bushings to appropriate for this caliber, I decided on this variation. I cut a seating die with the chamber reamer in a wilson blank).

I chose a Bat M action with 1.125 tenon RB RP R eject with a hart interupted fluted 27 inch barrel. I did the metal work & had Alex Sitman put it in one of his special custom laminted thumbhole stocks. I ordered blue/gray but it came back an aqua green and is just gorgeous (3 pilar bedded).

The experience... I can shoot 100 yds here at the house & was a bit disappointed as the smallest groups i could get were nickel to quarter size groups (very many bullet /powder combinations). In comparison to my 6xc and my various 6ppc bench guns it was quite diapppointing.

Yesterday we shot at my shooting buddy David's farm where we can shoot out to 500 & decided to try working up loads at 500.

Here is the cool part.... without problem we got the rifle to shooting 5 shot groups of 1/2 to 3/4 inch center to center. Needless to say I was thrilled. I've shot very little past 200 yds so I don't have much to go on.. but this seems like a good shooting rifle!...

Heres the puzzlng part :confused:

David likes to shoot those groundhog shoots where one shoots 100, 300 and 500 yds.. this rifle should be a killer in that game...since its shooting a much heavier bullet compared to whats most commonly used in that game. it ought to be less wind sensitive for sure...

Thinking the good groups at 500yds will translate to little groups at 100 we eagerly set up for 100 yd testing only to find grouping at 100yds in the 1/2 inch range...

I guess she don't go to sleep until quite some distance past 100...Even though I see it.. it still don't seem logical (When thinking in terms of geometry)

Is this phenomenon common in the 6.5mm family?? I have another friend who has a 6.5-284 that told me his rifle exhibits the same characteristics...He feels like the further he shoots, the better his groups.are... (his range allows shooting out to 475).

Sorry for such a long post... I just had to share...

Kirk
 
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Kirk,

I'm at a loss to explain the big groups at 100 also. I'm sure you checked already to make sure that you were not suffering from wicked parallex error. In my experience rifles don't shoot better with increasing range, ever. And I can't find any science to explain that behavior either. But the more I learn the less I know. What I am sure of is that the accuracy you're getting at 500 yds deserves to be be exploited in a less casual venue than your buddies farm. Get on over to ORSA/Oak Ridge on April 24 for the IBS 600 BR match and let that magic shine in the light! And quit shooting it at 100!

Greg
 
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You asked if bad 100 yard groups were normal with the 6.5mm chamberings. Well i dont know about all that really. but what i do know is that i had a 6.5 creedmoor that shot dots at 100 yards with 130gr berger vld. If i were you i would try a lighter weight non wild type bullet for your close range work if you cant get your rifle shooting any better. Im pretty new and i am learning as i go, but i have never herd of a situation quite like yours. There are some great fellas here with lots of knowledge, so maybe you can get some better help here in a bit. Good luck, and take the fellas advise, go to a 600 yard shoot and give your rifle a work out!! Lee
 
Accuracy...

I read the post and replies and I may be missing something, but what is the weight and length of the bullet and twist of the barrel? How did you settle on a load and seating depth? What is the velocity? Just curious. nhk
 
100 yd grouping

i was not really asking if bad grouping @ 100 is normal... Just if they seemed to group better at longer distance.. ie they "go to sleep" further away.. another of my friends with a 6.5-284 xp100 has related to me that his rig shoots really so'so @ 100/200 but really good at 500.. the 6.5 bullets are really long compared to my 6mm fodder. This grouping deal has to be caused by the bullet stabilizing (going to sleep) further down range, there is no other real explanation in my mind.

it don't shoot "better" @ 500,,, just the same..which translates to better in comparison.. I've never had one like this either, hence my post. obviously the geometry of the different distances has nothing to do with the grouping or the 100 yd groups would be in the 1's

I start all my tuning with the bullet seated where the lands "mark" just disappear. i start here with all of my rifle.
I then, during development, shoot test groups as far as 20 thou off the lands to max in the lands of a square mark.. this barrel is 8 twist hart with a 120 grain sierra bullet... i've not chrono'd it yet but expect it to be around 2800 fps. . i have several other bullets to try that i put away because of poor grouping here at the house.. they will be tested @ 500 now. as will the others.. The bullet selection for the 6.5 is relatively small, & i have probably most of em if they were offered in the lower weights suitable for the small case capacity...

Skeetlee what is a "non wild" type bullet? Is anyone other than "Swampworks" making custom 6.5 bullets? i'm really on the low end of knowlege regarding the various 6.5s.

Greg.. I built this rifle with Oak Ridge in mind.. I chose this round because Of Don Nielson's winning the 600 yd nationals a couple yrs ago with the 6.5x47 lapua. (the only real diff between an XC and the Lapua is the lapua has the small rifle primer, The xc large.. the spec differences other wise on the cartridge are so minor as to be negligible. ) i had intentions of trying the lapua brass but now see no reason to other than curiosity. I had bought 1000 of the JLK 130 grain bullets because of Nielson's win too. they were not too hot @ 100..but.they will be tested again for sure...

could you email me @ kirktink@earthlink.net with pertinent info for the Oak Ridge match...clue me in on 600 yd competiton.... ie how many rounds do we fire for record ect.. Is it just like a short range bench match, but 600 yds?(both group size and score are recorded??) I live in Bulls Gap, Tn which is no more than 2 hours from Oak Ridge. hopefully i will get to go!!

Thanks much,,

Kirk

ps.. the shooting was done really early in perfect condition.. really really light steady to no wind, no mirage..in other words nothing like occurs during competition.
 
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You said that you don't usually shoot so far out. Are you using a different scope on this distance gun -vs- the known 100yd groupers?

I wonder if parallax is taken out at 100yds -as accurately as 500yds..
It is easier to lock into 'parallax free' at 500
I wonder, because I have always shot tighter moa further out(and I don't even bother shooting this side of 200 anymore).

Aside from grouping ability, how is the accuracy?
Are sighters even allowed in your GH shoots?
 
stuff

there is no scope problem this is a Nightforce scope that is really awesome

The ground hog shoot i'm speaking of is the "Hickory Egg Shoot" The target is a groundhog silouette with a 3/4 inch white dot on its head and a couple larger scoring rings out to abouth 2.5 inches It has an 1.5 inch dot on its chest with a couple more larger scoring rings out to 3.75 inches. the head scores higher than the chest..

the scoring is "inside out" ie the lowest score the bullet touches is what is recorded. most people shoot the head @ 100 & chest @ 300. any points @ 500 are just bonus as most of the time its won from points @ 100 and 300.. you need to ace the 100 & 300 to be in the race.. the year i shot it a guy with a Savage custom shop 223 won it (near dead calm, overcast day). most yrs its a variation of 6mm . (many variations of BR, ppc 243 6xc.) custom bench gun. that win..though its a shoot what you bring match. You also get to fire 1 shot at a real egg at 500yds...hence the name.

when i went, no foulers/sighters were allowed. & 3 shots recorded at each distance.. they run the shooters through quick ie not much time for set up. They say registration is the morning of the shoot though several early relays are full no matter how close to the front of the line you are????

Its a fun shoot for "braggin rights with your buddies " as far as i'm concerned. . if one is serious about it, the 100 needs to be aced (300 too).

I hear these type shoots are very popular up Pennsylvania way??

Kirk
 
Kirk
Did you chronograph your loads? I have seen loads with a higher than normal extreme spread do as you have described.Tuners also do the same thing you described.
On the JLK bullets not shooting well I think The Pumpkin had Bartlien make him a barrel to fit the bullets.He recently shot 2 world records with it at Sacramento so the barrel is working.
Waterboy
 
Sounds like a great match format to me, and it sounds like you're gonna be prepared. I wasn't really thinking a 'bad' scope. More like the difference in dialing out parallax from long ranges to short.

It may just be a crazy notion, but it seems very easy to accept a parallax setting up close, at high power, -that might not be truly accurate.
Could depend on the target I suppose..
But at distance, it's very easy to know a perfect setting, as you can hardly see the mark until all parallax is dialed out.

Just throwin it out there
 
A wild bullets is equal to my lack of typing skills. vld is what i meant to type. Sorry for the confusion. On another note, I noticed that you stated that you start your bullet seating were the and marks just disappear. That's probably not a terrible idea but by doing this you will have to go possible both ways to find were your bullets wants to be. If you would start at the jam length then you only half to work one way (that being down). Thats just one little tip that was passed on to me by the good folks here. Good luck and i hope you get everything worked out! Lee
 
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i built a 308 that shoot pretty mediocre (1\/2" or so) at 100yds but shoots 2"-3" groups at 550yds consistently. i consider this very good. i dont know if i read your post correctly but are you saying you are shoot 1/2"-3/4" groups at 600yds or 1/2moa-3/4moa at 600yds? if it is the former, you should go shoot a few world records and be happy. if it is the latter, it is still shooting very well i think. i built a friend a 338EDGE and he shoots the 300gr sierra MK. it shoots .6 or so at 100yds but really shines way out there. 100yds certainly doesnt tell the whole story unless you are shooting 100/200 BR or score matches.

chuck

chuck
 
Kirk Ethridge said:
Here is the cool part.... without problem we got the rifle to shooting 5 shot groups of 1/2 to 3/4 inch center to center.
Click to expand...

So, your rifle is shooting 0.955 to 0.143 MOA at 500y without problem... five shot groups.

Yep, like the other gent said, why are you wasting time at a farm when you can be winning matches and setting records.
 
Hi

Hi Kirk,
I have a 7mm-08 that seems to have the same problem. I am shooting the Sierra 168 SMKs out of a 1-10 twist barrel. They are supposed to be right on the ragged edge of stability and at 100, my results are usually .6 or more. However, while practicing for the Hickory match this year, I shot 5 out of 6 groups at 500 less than 3 inches. Perhaps you should measure the twist in your barrel with a cleaning rod and try a lighter bullet. Next year I am going to work up a separate load for 100 and 300 yards, but keep the existing load for 500.

Joe
 
When I first began shooting for accuracy, an old fellow that
came to the range often told me his 6.5-300 wby would not shoot
at 100, but went to work some time later. This made no sense at
all. How a wide shot could come back in thereby shrinking the
MOA all by itself, began many questions. I called Homer Powley
and Robert Hutton. Homer sent me a set of targets that were all
shot with the targets in align but at different yardages. This done
for one group.Apparently The farthest target was set and without
moving the gun, the next target closer was set and so on. He said,
it was possible for bullets at different velocitys or BC to cross paths
at different distances, but only outside forces could pull them back
in horizontally.
 
I very rarely shoot my rifles at 100yds, not realy worth it and I dont have the time. I do know that the loads I have which shoot very well at 600-1000yds, keeping well inside a 1/2 moa x ring in verticle (not wind), dont realy set the world on fire at 100yds. For a few reasons.
Maybe parrelax wasnt set quite as exact.
Maybe my hold wasnt quite as good.
The bullets epicyclic swerve or wobble or what ever its called, might not have quite settled down.
The main reason I think though is that my (and most other long range shooters) loads are tuned for minimum verticle at 600-1000yds, so that the shots with the slightly faster muzzle velocity exit the barrel further down in the vibration cycle, while the ones which are slower than average leave the muzzle when it is high up in the vibration cycle. On the rare occaision that I have fired my rifle over the crony with my good long range loads, the bullets which hit higher up in the group were the lowest in velocity and vica versa.

Once the bullets get further down range, the low grouping faster bullets, catch up and hit in the center of the group.
 
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