Trouble getting a group

[wdallis]

I am shooting a .270 wincester, using a 140 grain jacketed bullet with a minimum powder charge of 50.7 grains. I could not even shoot a 4 inch pattern at 100 yards out of a gun vise. I started thinking that my powder dispenser might not be throwing consistent charges, so I check 10 loads, weighing each one of them with my power dispenser set to throw 50.7 grains and this is how they weighed out in my powder scale as followed:

01. 51.5
02. 51.7
03. 51.0
04. 50.0
05. 51.5
06. 50.7
07. 50.6
08. 50.5
09. 50.9
10. 49.8
I seriously think I need to start weighing every charge to get accurate results, but I thought I would get some thoughts from you folks as to weighing each load or if there was something else I could try? In desperate need to shoot atleast 3/4 inch groups at 100 yards.

 

[MEHavey]

That weight variation, while not ideal, is not likely the cause of your group problems. (Hatcher tells of very good 30-06 match ammunition being issued by the arsenals with more than twice that spread.)

What are the details of the load . . . ?
Powder type/amount, case manufacturer, bullet type/make/weight, primer, and overall cartridge length?

And who makes the rifle?

 

[James2]

Yes, more info needed.

Has the rifle ever shot groups like you want with any ammo?
Did you try a little faster load? More powder?
Have you tried a different bullet?

I tried several powders in my 270 without much luck until I tried IMR 4831. Good powder for 270. The large case capacity with a rather small neck diameter seems to be a bad combo for any faster powders.

 

[osprey176]

270 woes

4 inch groups tell me you have a rifle problem,not a load problem.check your bedding first,actually i would pull the action out of the stock and look for anything obvious like cracks.reassemble and tighten the guard screws snug,plus a little more.check your scope,you may well have a loose mount.i would remove the scope and remount it using loctite,or finger nail polish on all the screws.clean the bore good,use a bore cleaner,then Barnes CR 10 for copper,i have found none better.finally i would forget the vise,as they are great for working on rifles,but not for shooting them.use a good,solid,padded front rest,and pad the butt end under your hand.make sure you are shooting off a sturdy bench,they dont group well off light tables.you may even try a box of factory loads,remington corelockts shoot well in several of my rifles. sorry for the long response,but i have been down that road before.let me know how you fare. steve

 

[wdallis]

I am using the following mixture:
Powder- IMR4831
Powder charge is supposed to be 50.7 like I stated in the first post
Case type is winchester
Bullets- Nosler accubond 140 grain boat tail
winchester primer
OAL- 4.434"

Hope this helps you

 

[shaggy430]

Weigh each load so you can at least eliminate that part of the equation. I always weigh each load when loading rifle powder, especially stick powder like 4831.

 

[MEHavey]

Charge/cartridge combo appears OK.

As my neurologist often tells me, 90% of the diagnosis comes from the history.
That said...

How long have you had the rifle? Who makes it? Has it ever shot good groups w/ any ammunition for you before? (And do you know the twist rate? [1-in-10? or 1-in12])

What scope and how long have you had it? Do you have an option to change the scope out (or try it on a different rifle) to eliminate it as the problem?

Have you checked the barrel's free float? (Are you able to get a sheet of common printer paper between the barrel and stock all the way back to the chamber/receiver?)

Have you checked the receiver screws and/or tightened them if loose?

Have you pulled the action to look for anomalies and/or cracks?


Run that checklist and see if anything obvious rears its head.
And last shall be as first again: Who made the rifle?

 

[243winxb]

OAL- 4.434"

Type O? or the correct COL. Seat the bullets base (full diameter) at the neck shoulder junction of the brass. A boatail will be below the neck/shoulder junction. Weight each powder charge. Load 3 or 5 of each as you increase powder by 1/2gr, working towards maximum. Your using a slow burn rate of powder, so it may work better Hotter. Averager for a factory gun is 1 1/2" to 1" @ 100yds. You would have to get very lucky, have a great barrel, to average under 1"

 

[MEHavey]

243winb... I assumed that a typo

 

[Ruark]

Could be all kinds of things. It could be one of the factors mentioned here - lots of good advice. Or it could be too much headspace (distance between the bullet and the barrel), variance in brass, which can mean variance in case neck tension or length, wall thickness, primer seating depth, crosswinds at the shooting range, dirty barrel, faulty scope, etc. It's a long list. And even with a bench vise, you could still be flinching when you pull the trigger.

And I personally don't think your powder measure should vary THAT much. I use an inexpensive RCBS Lil' Dandy, and it consistently throws loads that are +/- .1 gr.

When you finally figure this out, let us know!

 

[wdallis]

Well I have been narrowing down the objectives. First I found my barrel to be setting on the front part of my stock, so sanded that down to where it is floating again. Barrell was not dirty, but cleaned it anyways. You guys were so right about the typo, supposed to have been 3.434. sorry bout that. I have had the gun/scope for bout 4 years. It will shoot about 1 inch patterns with factory ammo at 100, so I assume the barrel is good. Not sure what the twist of the barrel is, but it is a savage model 110 .270, if that helps you. I really appreciate you folks help. I hope to get this problem nipped in the but. I am out of bullets right now hope to be getting some more this weekend, will keep you guys up to date on the results. thanks again. oh yea one last bit of info, the bullet is setting about .010" off of the lands of the barrell.

 

[sansone]

Weigh each load so you can at least eliminate that part of the equation. I always weigh each load when loading rifle powder, especially stick powder like 4831.

me too.. I even use brass fired from the same rifle and neck-size only. I also weigh the projectiles for equal weights. My buddy weighs the empty cases and sorts them

 

[JimKirk]

Shotguns shoot patterns...rifles shoots groups.

I think you have got some good advice from the guys above. I have one more suggestion...take that powder measure out back and shoot it! If you can't get better measurements from it, then put it out of your misery! What brand are you using?

Jimmy K

 

[wdallis]

Its called a lee perfect powder measure, cheap kit. I figured it was junk when I bought it. I have an RCBS 5-0-5 scale coming in the mail in the next couple days. I guess I will weigh every charge til I can get a good powder dispenser. The Lee might do good with short cut powder though, haven't tried that.

 

[brickeyee]

Or it could be too much headspace (distance between the bullet and the barrel)...

Except that bullet to barrel is NOT headspace.

Headspace is bolt face to datum (on the shoulder of most bottle necked cartridges).

The closest thing to bullet to barrel is bullet to start of the rifling ('freebore' if left long on purpose in the barrel).

 

[jcwit]

Its called a lee perfect powder measure, cheap kit. I figured it was junk when I bought it.

Contrary to what many tell you or think the Lee measure is a very accurate measure. Some folks have trouble with some powders in that they do not know how to set the tension screw and/or fail to run a few hoppers full to break in the measure and naturally lube it with the graphit from the powder.

Remember also most benchrest shooters do not weigh their powder while loading.

I think post #7 is more on track.

 

[murf]

after you get the powder-measuring issue sorted out, try a different primer (i suggest BR2 from CCI).

murf

 

[Ruark]

I'm not sure if it applies here, but in SOME cases, a powder that doesn't fill much of the case can cause inconsistency issues. The idea is that the powder sloshes around in the case and is in a different position for each shot... down at the primer end for one shot, down at the bullet end for the next shot, etc. That's one reason the .308 is used for long range bench rest shooting: the best .308 loads completely fill the case. I know that's a long shot (no pun intended!), but I just thought I'd throw it in.

 

[NCsmitty]

It's possible that your rifle may never shoot that 140gr bullet well, but you first need to eliminate the powder variations that you show. When working up loads, scaling each charge weight should be done to give you good feedback. When you find a load that works, then you can mess around with dropping charges from the measure directly.
Most 270's work very well with the 130gr bullet versions, and I suggest trying that weight.



NCsmitty

 

[Sin City Shootist]

I'm going to jump on the "check your scope base and rings for tightness" bandwagon.

 

[Chief RID]

I would shoot another group with some factory ammo to make sure something has not happened with the rifle. You need a powder scale. It takes practice to throw consistent charges with a powder measure and there is no way to practice and check your measure without a scale. You should check your measure every 10 rounds anyway.

 

[45Fan]

Sounds like good advice so far, not much that I could add. When loading for my bolt guns, I do weigh every load, I set the thrower just under, and trickle up to the charge. It takes a little longer, but it takes that posibility out of any issues I might run into.

 

[DANNY-L]

I would also buy some cheaper 140's until you get your problem solved then move to the nosler for fine tuning,it would save a few bucks. Trickle charge each round. A couple of years ago I bought a new 5-0-5 and it was not consistant at all,I sent it back to a'haus (rcbs) and when it came back it worked fine. I also bought a hornady GS1500 electronic to double check once in a while. My opinion if everything with the rifle and scope is good give imr4350 a try.

 

[wdallis]

45Fan ----By weighing every load, what kinda pattern does that let you shoot at 100 yds?

 

[WNTFW]

Sorry if I echo some of the other post.(I didn't read every one, just skimmed)
Check the muzzle/crown for damage.
check other obvious/previously mentioned items for problems.(bases, rings, action)
Check the scope for something like an eyepiece/ocular lense that is loose.
I would also suggest getting off the vise and trying it prone or benched.

I always weigh every charge when working up loads. Then when I start using a load I weigh all the first batch. As the load proves out to be good I start weighing less and relying on the powder measure. That elimates variables and proves the powder/thrower results.

Can you post some target pics, so we can see how the groups look? Point is to see how the groups string.