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.243 problems and questions

Discussion in 'Handloading and Reloading' started by cheeze, Jul 16, 2012.

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  1. cheeze

    cheeze Member

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    Hello, bit of a long read, but I would appreciate some advice if you can spare the time.

    I have been working on .243 accuracy for a little while now. I started off with a stock winchester 670 (basically a no-frills model 70 with sport barrel). Accuracy was not good. I inspected the rifle and could find no problems other than suspect bedding problems, so I bought a hogue overmolded stock with aluminum pillar bedding. Accuracy didn't improve much. I performed some trigger work, removing the extra travel, lightening the pull, honing the catch. Sweet trigger, still wide groups. All testing is done at 100 yards on match target and benchrest. These rifles are known to perform 1/2moa or better.

    I have been using varied charges of IMR4831 behind speer and hornady 85 and 100gr bullets set at varied depths in the case. Best I could get with that was about a 2" group with occasional fliers that were not my fault. I started using fire-formed cases, no crimp, bullet seated out closer to the lands, matching headstamps and uniformly trimmed cases. Still no dice... 2moa+. Best load was 42.5 gr at ~2875 fps on the chrono.

    I had a bit of a different powder available that was given to me (IMR 4895) and although my current book doesn't give data for it, an older book did. I started with 33 grains. 3 1/2" moa. At 35 grains, I got a group just under 1" (eureka!!!... I was beginning to think something was wrong with the rifle). That got me ~2820 fps. This with a 100 grain hornady spbt.

    I think I can work with this, tweak it, and make it better, but I have a concern. I understand that IMR4895 is a bit fast for this heavy of a bullet. If so, that would make pressures higher than ideal in the chamber and barrel. I don't want to erode my barrel faster than normal. Any ideas on this? Should I try a few other powders before settling on one, or should I see if I can work with this and get my desired 1/2 moa? Anything else you might suggest?

    Thanks for your opinions!
     
    Last edited: Jul 16, 2012
  2. steve4102

    steve4102 Member

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    Hodgdon has data for IMR 4895 with your bullets weights. Use it and work up and you should be fine as far a pressure goes.
    http://data.hodgdon.com/cartridge_load.asp

    I have my doubts that a 2gr increase in powder took a 3 1/2 inch group and turned it into an MOA group. Maybe, but it sounds more like a fluke to me. Did you get this "almost 1 inch" group more than once?

    Have you checked the optics and mounts on this rifle. Have you swapped the scope out with one of known accuracy?
     
  3. ranger335v

    ranger335v Member

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    First, .243 is not unique and some rifles are 2 moa shooters so no load can change that. And, as Steve menions, scopes matter too.

    Next, no other factor for accuracy is as critical as the bullet. Some rifles hate a lot of bullets and no load work up can change that. When - and if - you find a bullet the rifle likes it can make a radicial improvement in accuracy.
     
  4. rcmodel

    rcmodel Member in memoriam

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    According to Hodgdon data.

    A max load of IMR-4895 (35.7) gives slightly lower pressure then a Max load of IMR-4831 (43.0).
    Also slightly less velocity.

    So, you are burning almost 10.0 grains less powder, at slightly less pressure and velocity.

    That should translate into longer barrel life, not shorter.

    rc
     
  5. cheeze

    cheeze Member

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    Steve, like you, I couldn't believe how the group settled in with the 2 grain increase. I got 2 groups of 5 shots at around 1", then went back with the 33 grain loads and the group opened way back up. I shot one more group of the hotter loads and got another ~1" group. This pretty much leads me to think it wasn't a fluke or the rifle or optics. I have tried a scope from another working rifle, same results. I didn't try swapping the mounts, but I'm not convinced that is the problem yet.

    Ranger, I know some rifles are just not as accurate, and if mine is one, then so be it. I did finally get it down to 1" for the first time though, so I just wonder if I can get it even better. I thought about trying other bullets also, but I got the same results (consistency), ranging from about 3" to 1" with both bullets. Speer 85grain spfb and hornady 100 grain btsp. I got the 100 grainers into 1" with a 35 grain 4895 charge, and a 36 grain charge on the 85 grain bullets. This makes me think it's not a difference of opinion between the rifle and the bullets, but something else? Would you agree, or is my logic flawed? I don't doubt that there may be a bullet that performs exceptionally in my rifle that I haven't found yet, but do you think the bullet is the fault that causes groups from 1" to over 3"? Thanks!

    rcmodel, thanks. If you were in this situation, what would be your next step to improve accuracy?
     
  6. rcmodel

    rcmodel Member in memoriam

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    Quite frankly, if you are getting under 1 MOA now with a Model 70 Sporter?

    I might Bee Happy!

    A 1/2 MOA might have your sights set a little high for any average sporter weight .243.

    rc
     
  7. jim243

    jim243 Member

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    Yes and No. The most important factor is your barrel harmonics. Is the bullet leaving the barrel at just the right moment when the barrel is in mid cycle.

    This is a factor of both the barrel length and bullet weight and also the speed at which the bullet leaves the barrel.

    Factors that will make this up are bullet weight, amount and type of gun powder, barrel lenght, AND jump to lands.

    Since no two guns are the same even from the same mfg and same model. Each rifle has to be tuned to it's own perfect performing load.

    All we can do is give you generallization as to what our rifles do, for your rifle you will need to experiment.

    First thing is to overcome barrel whip, for my rifle (243 Winchester) (Savage Model 10 22 inch standard profile barrel), that is about at 2,900 FPS, but will depend on the type of steel and thickness of your barrel.

    Second, is fastest is not always the bestest (not sure that's a real word). So my loads tend to be under the max loads by a half a grain of powder or more.

    Next is bullet slection, I use the 105 grain Hornady A-Max's almost exclusively. Powder, H-4895, yes it works better for me than IMR-4350 or H-4350. Next is the weight of 31.0 grains of powder with sometimes up to 32.5 grains, but the 31 grains works better at getting small groups on paper at 100 yards.

    Next, are you going to jam that bullet into the line and groves or are you going to give it a jump from the case to the throat of the barrel. For me I find that if I give the bullet a 0.050 jump and do not jam the bullet in, it works like a charm for my rifles. I use the Hornady L-N-L gauge with adaptor case to find the MAX OAL for each different bullet type I use and then back off that OAL by 0.050 inches.

    And finally, the trigger pull must be perfect and smooth as glass. I use Savage rifles with the Accutrigger so that there is a clean break no over travel and it fires just as the scope is centered on the bullseye. A trigger job might be in order on your rifle to give you those sub-MOA groups.

    So yes you can get sub-MOA groups, but it will take a bit of work on your part.
    Good Shooting
    Jim.
     
    Last edited: Jul 16, 2012
  8. Kingcreek

    Kingcreek Member

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    I have a model 70 featherweight that shot horrible groups with everything. I tried everything I could think of before taking to one gunsmith who couldn't make it do any better after some stock work. Talked to a second gunsmith when picking up a 1911 and told him my tale of woe. Without even seeing the rifle, he suggested I pull the stock and reassemble with no more than snug tension on the front screw. It magically became a 1 MOA rifle and one of my favorites.
     
  9. Skyshot

    Skyshot Member

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    Cheeze, I would get 1 inch groups out of my Savage model 11 using 34.3 grains of IMR 4895 but the bullet was a Sierra game king. Going up to 35 grains the group would open to just above 2 inches and below 33.5 grains it became a shotgun pattern. I could not achieve good results with the Hornady and speer bullets you mentioned, but have had great results with the 87 grn. Hornady Vmax. I still like the 100 Sierra GMK and it does very well with IMR7828. Keep digging and you'll find a good recipe!
     
    Last edited: Sep 10, 2012
  10. murf

    murf Member

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    fire some factory ammo and get a baseline for future comparisons (bullet weight needs to be the same to compare).

    check your crown for dings. rcmodel has a quick-fix posted somewhere to fix, if needed.

    is your barrel supposed to be free-floated? if so, check it and make sure.

    what do your groups look like? are they stringing vertical or horizontal, or just randomly roundish?

    on a light rifle, holding the fore-end down hard, with your off hand, should shrink groups and reduce fliers.

    set the fore-end on the front rest in the same position every time. also, remove the front sling swivel if it contacts the front rest.

    eliminate parallax.

    if i think of more, i'll let you know.

    murf

    oh, and try imr 4064 if you get a chance.
     
  11. cheeze

    cheeze Member

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    Okay, lots of great suggestions.

    rcmodel, if 1moa is all I can get, I can live with that, but I keep seeing reports of 5 shot groups on 1/2" for these rifles in stock condition. The one with the light barrel (featherweight) seems to get 1" groups from what I've read. Mine doesn't have the heavy barrel, but it does have some meat to it... it's the middle weight barrel. I respect your opinion about this though, so as of now I will consider anything under 1 inch as gravy, but I'm gonna keep trying.

    Jim243,
    Thanks for the ideas. I think you hit the nail on the head mentioning whip. That is the only explanation I can think of for 2 grains of powder to make the difference between 1" and 3" groups. I think I will start making test loads in 10ths of a grain increments now to see where I get the best results. I think I will try those A-max bullets too. Can't hurt. I just want to stay on the heavy side for deer hunting. I haven't played with bullet jump much. This gun has a long throat from what I can tell. I'm loading currently to 2.700. As I recall, this is something like .020 off the lands for that particular bullet. The sierras hit a little closer. I did work on the trigger, it is very nice now.

    Kingcreek,
    Thanks, I will try that.

    Murf,
    100 grain winchester factory ammo got me in the 2" area with just under 2900 fps.

    I have inspected the crown under magnification and could find no dings or damage.

    The factory stock had the barrel floated, so I believe it should be. The factory stock was warped and contacting the barrel on the side of the fore end tip, so I went to the hogue because the barrel channel was already cut off-center and removing enough to eliminate the barrel contact would have really made it look bad.

    Group pattern: The wider they get, the rounder they get. As they tighten up, they consistently give me a diagonal pattern from top right to lower left... probably 50-60 degrees or so. Can you make anything of that?

    I'll try holding the forend down better. I wasn't doing that trying to remove as much tremor or other user-error from the equation as I could.

    My scope has adjustable parallax, and I try to get a good cheek-weld at the same spot every time, right at the spot where I get full-picture in the scope and no closer/further. Is there more to it than that?
     
  12. murf

    murf Member

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    check the barrel by running a dollar bill between the barrel and the stock. should go all the way to the action without sticking or binding.

    your groups diagonal stringing is from the stock touching the barrel or action on one side and not the other. the barrel should not touch, if free-floated. the action should only touch the stock: on the back of the recoil lug, the bottom of the receiver block and the bottom of the tang. no touching on the side or rear of the action.

    when pulling down on the stock with the off hand, make sure to do it the same every time, and don't shake. idea is to add weight to the gun (artificially), but the weight should be the same with each shot. this also helps decrease muzzle jump at recoil.

    the parallax adjustment ring or knob hash marks are not accurate. you should do a parallax check every time you change your shooting distance. test: with gun on rest, put cross-hairs on target, without touching the rifle with your face, or rest of body, move your head up and down, and back and forth. if the parallax is adjusted right, the cross-hairs will not move on the target. if they do move, adjust until they don't.

    murf
     
  13. Skyshot

    Skyshot Member

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    Cheeze, forgot to mention that you might try a Sims barrel De-resonator to play with the harmonics. Finding the right bullet/powder combo could be a challenge. I don't know what your research budget is, but I would try Several powders if you can. Seems to me if the gun is capable of 1 moa then it should get a little better(may be). If you have some IMR4895 and some H or IMR4831 why not try some RL-22 or some IMR4350 or 7828 or N560 or the like. I'd stick to the slower stuff if you plan on shooting heavier bullets for deer hunting. I'm thinking you can get what you want but it's going to take some research. Keep us posted, I'm interested to know because I've had my eye on a Model 70 featherweight .243 at one of LGS's in my area.
     
  14. wingman

    wingman Member

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    Try sierra 80 or 90gr matchking for accuracy with h4895.
     
  15. 243winxb

    243winxb Member

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    243 Winchester Accuracy

    The 670, with a barrel twist of 1-10 should do best with a 90gr or lighter/shorter bullets. Best powders IMR 4350 & H4350. IMR 4831 can work well with 90 gr, but is harder to find a load. Sierra 85 gr HPBT Gamekings are a good all purpose bullet from deer to woodchuck. Berger 90 gr HPBT match bullet will produce tight groups. Barrel clearence to stock should be more* than the thickness of a dollar bill. Expect average accuracy to be around 1" Some 5 shot groups will be smaller than 1" , some bigger. CCI Br2 primers, Win. or Rem brass work for me. Bench rest perp of brass has produced 5 shot groups under 1" @ 300 yds for me. Sorting brass by weight will get rid of flyers.
     
    Last edited: Jul 17, 2012
  16. RainDodger

    RainDodger Member

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    If you want to try a 90 grain bullet, I've found the Berger 90 gr Match BT (#24425) to be very accurate. I have a heavy-barrel Sako L579 that I couldn't get decent groups out of. I tried this 90 gr bullet with IMR-4064 and it was a whole different rifle. I traded emails with Walt Berger about it and he suggested experimenting with OAL. By setting the bullet about .005" behind the lands, I started getting really tight groups. .005" was making a difference of a good half inch at 100 yards.

    Sometimes it takes a lot of patience... in this case it kept me from getting rid of a nice rifle.

    Good luck.
     
  17. murf

    murf Member

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    might as well turn your case necks. and make sure the cases are all trimmed to the same length.

    pull out all the stops!

    murf
     
  18. popper

    popper Member

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    Try with fore-end on bags, left hand under the pistol grip and butt pulled tight against your shoulder. 2 sock Weatherbys (vangard, plastic stock, cheap china x9 scope) shoot 1/2" with no effort, no special brass treatment (crummy Lee die) and no load workup. Midrange H4895 with Hornady amax 55-75 g, 100 g SP.
     
  19. Coltdriver

    Coltdriver Member

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    Do some searching and find "optimum charge weight method".

    You already know that the rifle will shoot with a particular load.

    So we can probably rule out any fundamental problem with the platform.

    I have used OCW to dial in loads on many rifles. It is amazing and as you have discovered a couple of grains can be the difference between a good load and a poor load.

    Do your best to get to a target that is 200 yards out. The effect of variation in charge becomes very apparent and when it groups that too will be apparent.

    Spend a little time on Varmint Al's website. The man is a bonified scientist who loves to shoot. Once you get the concept of barrel whip or deformation under a particular load harmonic then understanding why OCW works becomes obvious. http://www.varmintal.com/amode.htm
     
  20. cheeze

    cheeze Member

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    I went to the reloading supply shop 30 miles away and picked up some speer grand slam 100gr bullets and some H4350. That was their only other heavy bullet choice aside from what I already have. They were expensive at $36.00 for 50. The powder choices were slim too. I plan to work with those components a bit too, as well as try to improve my IMR4895 loads that are already performing. I was shooting off a cheap outers bench rest, not bags. I think I'll sandbag it next time and I might strap it to a lead sled and see how that does. Have any of you used a lead sled? Is it a good way to determine the ability of a rifle while eliminating user error? I'm a very good shot, but I'm not a professional. I can put my 30-06 rounds through the same ragged hole off a sandbag at 100 yds though, so I should be able to with this as well.

    Coltdriver, thanks. I will check that site out and the OCW method. Our range is 100 yards. I can put the target all the way to the berm and maybe get to 125-130 yards, but that's about it. I used to have other places to shoot, but right now I can't. I know a guy with a 700 yard range at his place, and I may try to get out there once I have some loads that do decent at 100.

    Thanks for the ideas and info, keep it coming!
     
  21. GP100man

    GP100man Member

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    I bouht a cheapie 770 youth for my girls to shoot (no ejection problems yet)& the first load was IMR 4895 34grs. under a Hornady 85 gr. SP flat based bullet just off the lands , it shot a 1 hole group for 5 shots & just over an inch at 100 , I ain`t changing nuttin !!!
     
  22. popper

    popper Member

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    My LeadSled is a cleaning rack now. I prefer the bags, got the shooter's ridge shorty 4 bags, very stable and much easier to carry to the range. I prefer the BR position as I noted, let the recoil and bbl whip do it's thing, 243 is almost nothing and you find out the real characteristices. Holding onto the foreend will change POI and you can't do it the same every time. The vangards I'm shooting are 'off-the-rack' stock. They sell a guaranteed 1/2 MOA, just select the best off the line. So, some are better than others. If you want the 1/2 MOA you might not get it with your rifle. Any rifle will give an hour-glass patterning from low to high loads. You have to find the accuracy load.
     
  23. NCsmitty

    NCsmitty Member

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    The flat base Speer Grand Slam 100gr will likely be easier to stabilize in the 1in10" twist than the longer boat tail bullets that you have used. H4350 is usually a very good powder in the 243, and the start load of 37gr for 100gr bullet that's listed at the www.hodgdon.com site, should give you an indication of your rifle's potential with the Speer bullet.


    NCsmitty
     
  24. Sniper66

    Sniper66 Member

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    I shoot a Remington 700 VLS .243 with 58 gr Hornady V-Max, using Varget....don't recall just how much, but it's in the Hornady manual. The muzzle velocity is around 3500 fps I think. My groups are usually about 1" at 100 yds, but like you I had to adjust the trigger to get there and tweek the load. This rifle has become my 300+yd p-dog rifle. With a steady rest and this load I can lay the cross hair across the back of a prone p-dog and hit him dead center at 300+yds.....almost every time. When I don't it's me, not the rifle or the load.
     
  25. Huckelberry75

    Huckelberry75 Member

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    87gn Vmax are lightning in a buddie's .243. He is running H4359 and getting around 3200fps. They just flat kill stuff and are plenty heavy for most white tails.
     
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