Someone please explain

[rjtfroggy]

I thought I finally found a load for my 308- 42.8 grs. IMR 4895,155smk seated .022 off the lands,@ 100 it shot a 0.358 & 0.417 out of a 22" 12 twist SS barrel.
Now @ 200 I don't even want to meassure it(looks like a shotgun),at least 1.5" horizontal spread. Same weather conditions,same bench,same everything.Any Ideas?
Getting ready to give up on this gun,I put it together for 200 yard bench rest and it is starting to look like a mistake,Maybe I should just work on the 260rem for this.

[Elkbane]

Fixed or adjustable paralax scope? I'd check first that I had the parralax adjusted out of the scope. When you change the paralax setting such that the image is clear, that doesn't necessarily mean you are paralax free. WIth your head down on the stock and crosshairs centered on a target, move your eye a little left and right, then up and down. Does the crosshair stay on target or move a little? If it moves, make gradual changes to the paralax setting until the reticle stays centered on target. I may be preaching to the choir (for you - don't know your shooting habits), but most folk I see at the range have very limited understanding about how to set up their scope for successful shooting at distance. Most of the time, they just dial it until the image clears up, or set it to the range marks on the scope(even worse) and call it good. You can eaily put an inch of paralax related spread into a group at 200 yds by not having teh scope truly dialed in.

If that doesn't help, you may have to tune your load for 200 yards. It's not uncommon for a great long(er) distance load to NOT be the best short distance load.
Elkbane

[LHitchcox]

Parallax issues or possibly a breeze across the lane that you didn't notice. The breeze can swirl or blow across some part of the range and not be blowing where the shooter is. Wind flags are helpful.

[skypilot]

With a properly rigged rifle and setup, if it is shooting a consistent horizontal grouping with no environmental cause, or as Elkbane mentioned paralax, generally the cause is from inadequate/improper bedding or canting the rifle.

[CharlieNC]

I'm also working up loads for my first 308 and have like you found what works well at 100yds is not the best for 200yds. The 100yd groups are most affected by seating off the lands, while 200yds depends on the amount of powder. Also at 200 yd the best groups occur where the amount of powder has least effect on vertical drop (consistent with so called ladder test). Recently someone posted a wide range ladder test for their 308 which showed a major impact of amount of powder on horizontal spread; across that wide range of powder the vertical was pretty consistent. You did not mention how much work you did to work up the load, so maybe there is more to be learned before writing it off.

[rjtfroggy]

Elkbane parralax is the first thing I adj. when I get to the range,even before the bolt goes in.The scope is a fixed 20x and always tracks perfectly when checked.
weather was 83* calm winds, bright sunshine.
The scope has a Vortex level attached so I don't cant it.(taking no chances)
I have gone through probably 100 150grn, smk's and now about the same or more 155grn. smk's. I've run thhrough the entire load range from the sierra & speer manuals and worked them in .5, .3,& .1 increments.
I also ran this barrel as a 30br before and could not find a accurate load so I had it rechambered.
I think what I have is a $425 survey stake. two different calibers two less than stellar results.
Probably going to call NSS and see what is in stock, maybe a bull 243 for 200BR.

[acemisser]

I would say more than likely the bullet is unstable at that distance...Befor making any scope
changes or whatever try a longer bullet and see what happens...If your on paper try to shoot
a group without touching the scope....Some people are constently playing with the scope
and have no idea what is going on....I never adjust the scope while load testing..Like I said,if your
on paper,go for group...Please let us know what it is doing...

[darkker]

I'm jumping in the "wrong bullet" bandwagon. My 175 SMK's have a HORRIBLE group @ 200. But is sub moa @ 1,000.
For that close, I really would suggest a flat base bullet.
What are your velocities? Nosler Custom Comps(155) really don't like to shoot unless I am running extremely quick, or quite slow FWIW

[82boy]

To start , there is more to this than meets the picture. You say everything is the same, and there may be some similarities I would say that not everything is the same. Some have claimed a load is good today, and gone tommarow, this could be what happing. Powder will change it weight as the day goes one, this is why it is good to measure by volume, but you may need to tweek the load as the day progreses. A few things comes to my mind, and one is this the same lot number of powder? I have seen lots very to extreams from lot number to lot number, so much that one lot may behave like a complete diferent powder.

On bullets to start how do you know they are all seated the same depth? When I get a box of bullets I measure them by ogive, and in many cases I will find 2 or 3 diferent ogive lengths in a single box of 100 bullets. What this means is diferent ogive length diferent seating depth. Also you may be close on seathing depth but not right on. Try tuning the load at 200 yards, and forget about 100 yards. It could be that this bullet is just not right for 200 yards, I know a few competitive benchrest shooters that will shoot one bullet at 100 yards, and another bullet at 200 yards.

A few other things that come to mind is one is light condition, light will change bullet impacts, The old saying is "lights up sights up." You may be encountering heavy mirage, there could be something out inbetween you and the target that is causeing mirage, wood chips are a great for putting out tons of thermals. NEVER SHOOT IN A BOIL! Watch the mirage, some of the best benchrest shooters I know will not look at windflags, but will shoot watching the mirage through the scope.

Last thing Froggy dont give up. Finding out what makes these things shoot funny makes you a better shooter.

[rjtfroggy]

82boy when seating bullets I use the Sinclair nut on all of them and I also meassure the oal, with this rifle I am using a micrometer seating die for consistency. As for the powder it all came from the same 8lb. keg so I hope it is from the same lot.
My loading may differ from everyone elses but I try to be a perfectionist with my BR loads. All cases are cleaned in and out primer pockets cleaned fl sized then chamferred and debured then cleaned again.I drop onto a digital scale from a chargemaster,then to a balance scale(to double check).After seating I use the "nut" then meassure to the tip usually with in +/-.002 or less. When done I have probaly spent well over 3 hours not counting the cleaning in the vibrator for 50 rounds. this last time 20 rounds as close to perfect as I can make them was over 2 hours of measuring & weighing.
This last test was shot as 5 round groups but using the 10 minute score style of shooting for each group. Mirage wasn't bad the range is all grass covered and the 200 yard targets are elevated behind a military type pit(they run quite a few service rifle comps here).
Lastly I am sure even you have gotten one bad barrel in your shooting life, and said to heck with this one.This one has gotten very expensive between the cost of the barrel, the cost of components and the gas back and forth to the range trying to make it work. When on a fixed income sooner or later one needs to stop but I may try one more time before I do.

[earl39]

at least 1.5" horizontal spread.

Froggy what was the vertical spread? I have noticed on my 308's that vertical relates to the load and horizontal relates to seating depth.

[rjtfroggy]

Earl all shots were pretty much at the same level,maybe at the most 1/8th.

[rjtfroggy]

I am going to try one more time. I will be adjusting seating depth .003 at a time using the most accurate load to date at the depth that it was for it.maybe 21-24 more rounds.

[82boy]

82boy ... Lastly I am sure even you have gotten one bad barrel in your shooting life, and said to heck with this one.This one has gotten very expensive between the cost of the barrel, the cost of components and the gas back and forth to the range trying to make it work. When on a fixed income sooner or later one needs to stop but I may try one more time before I do.

Honestly, I have only had 1 barrel in my life that frustarted me to the point where you are at. I still got the barrel and I am hopping that there is something else to this than it being a bad barrel. This barrel is an odd ball caliber that was little to no information loads developement on the internet, and it is one I dont have much experince with, and I contribute it to that, but that barrel shoots bad at any yardage.

Besides that barre,l I have never seen a barrel that was as bad as your describing, especialy a Douglas. (Trust me, I have owned a few of them.) Now I have had barrels that shot better than others, but the ones that shot worse was still able ro shot desecent groups at any distance. I mostly shoot 6 PPC, and I have barrels that seem to shoot bad, but they will still shoot a .3 area 100 yard group, and something in the .6 are at 200 yards. They are not up to my standard for a registered shoot barrel, but they will still shoot.

I would also say you are too anal about your loading, you dont need to do all of that to shoot good groups, In a registered benchrest match there is not enough time between relays to do all of that, and them guys shoot good.

[rjtfroggy]

.

I would also say you are too anal about your loading, you dont need to do all of that to shoot good groups, In a registered benchrest match there is not enough time between relays to do all of that, and them guys shoot good.[/QUOTE]

And there lies the problem the matches I shoot in are for score.Check the last IBS record match in Southington Ct.over last week end and see what I am trying to shoot against,about 1/3rd of those shooters show up each month.
My OCD reloading regime is all about this,getting the smallest group possible then trying to keep 5 dead center seperately.Almost every gun at these matches are custom made varmint for score guns and I am trying with my modified Savages. It sure aint apples to apples but I have been improving every time out.
Oh by the way I am not listed in the match I decided to be the dedicated target crew to keep everything running smoothly had 3-4 helpers but they also shot so it slowed down a little.

[Dennis]

Froggy, I have 4 308's that all drive mini tacks @ 100, 300, and 600! I have tried most everything out there. I have 10, 11, and 12 twist. Most are 28" long-bull barrels. I just shot a match last Saturday and the shooters using 308's in the F/TR Class were awesome! In talking with several, most of us were around the same load and bullets. I will PM you with some information.