What is causing this?? .243 load

[BigBamBoo]

So I have been working on a load for my fast twist .243,1:7.5) using 107SMK's and RL-19, RL-22, N165, and IMR-4350. No matter what I do I continue to get these type of groups. Even having someone else shoot the rifle results in the same type groups. I get 3 in the same hole then two flyers.

Any suggestions?

Thanks

 

[Rath]

What bbl profile are you using, I'm wondering if it might be a heating problem. Also are you doing anything at all different between shots. If you can bring your flyers in you have a nice group @ 300.

Also, is it always a similar pattern, ie: do the flyers group together and to the right or are they random?

Rath

 

[BigBamBoo]

Hello.
No they are random. I do not think it is a heat issue. Barrel is a Kriger heavy varmint style. The fliers can be the first shot or the last or anywhere in between. It is very strange.

I am going to try some different bullets and primers and see if it still happens.

Take care

 

[BigBamBoo]

Hi Lynn.
Yes...the rifle seems to work best with the bullets in the lands. I did try jumping them a bit, but the groups opened up.

Take care

 

[earl39]

BamBoo this may sound crazy but think about humoring an old man and try jumping the bullets in excess of 100 thousandths if you can without compressing the load. try 150 and 200 thousandths off the lands.

Gary

 

[mason]

I'm having the same problems with my 6BR i have a post on the main message board. I think it might be caused from neck tension in my case,, maybe we can work together and figure this problem out..Take a look at the groups on my post and see if this looks like the same problems your having..Also check your action screws if there to tight this can happen.

 

[normmatzen]

I think Mason is right, my 243 win, 1 in 8 105 A-MAX likes 0.080-0.1 jump.

 

[Moderator]

The top target is not a bad group at all for 300 yards, even with the split group. When we see results like this, the first culprit is simply wind. You didn't list your velocity, but assuming 3100 fps, a 2 MPH wind change,at 90 degrees) will move your bullet ONE INCH.,The same shift at 100 yards is only 0.1')

Remember even if you think the wind is 'calm' a 1 mph left going to a 1 mph right is a 2 MPH 90-degree shift.

Most shooters won't pick up a 2 mph change downrange. Even experts with the best wind flags can miss it.

Culprit 2: After your 'flyer' look at your rear bag. A mis-alignment can cause this easily.

Culprit 3: Are you changing your hand or cheek pressure on the gun at all?

Culprit 4: If you pull the trigger to one side or another it will be enough to alter the bullet's flight unless you have a super-heavy gun. If you don't believe this... practice with a good rimfire for a while.

 

[expiper]

Set right there and shoot about 20-25 rounds ...it is either the wind or the scope....as a matter of fact I would change to a scope of known dependability 'right NOW',you have allready went to a different bullet....dont waste any more coponents or bbl round count or your time....let us know what you find out....Roger
PS...be shure and shoot over wind flags...if you arent ...you are just wasting eveything...

 

[BigBamBoo]

Thanks for all the help. I have at least 30+ targets shot at different locations, and times. I am pretty sure it is not the wind. And if you look at the 100yrd targets it has the same thing. I know it's not the scope,Night Force)...tried another,Bushnell Elite 6500) and the result is always the same. Heck...even a broke watch is right twice a day. And again...have had others who shoot very well shoot it and they get the same results.


I will try jumping the bullets and see what happens.

I am not the worlds best shot, but I do ok once in awhile...here are 5, five shot groups using a $500 rifle shot at 100yrds from the prone with bi-pod and rear bag.

I will post the new results when I can get to the range.

Thanks again everyone.

 

[j_22250]

what bullets and what type of powder measure are you using? do you weigh every charge and is your rifle bedded?

 

[BigBamBoo]

I use a RCBS Charge Master for my powder measure/dispenser. So yes..every charge is measured. Bullets are 107 SMK's...rifle is a .243 with a 1:7.5 twist.

The rifle is a chassis type so no bedding.


Take care,Stan

 

[j_22250]

i would check your scale by weighing every single charge. i'm not sure if your doing this already, +/- 1gr. would cause that to happen.

i usually tend to have more fliers w/ imr4350 over some hodgden powders. i've never used alliant powders, but supposed to be good stuff.

what do you mean by chasis type, i've never heard this before?

 

[BigBamBoo]

I sent you a PM...a chassis type rifle like a Sako TRG-22 or Accuracy International AW,etc. No conventional stock. Receiver is bonded to the chassis so no bedding,etc.

Take care

 

[BigBamBoo]

BamBoo this may sound crazy but think about humoring an old man and try jumping the bullets in excess of 100 thousandths if you can without compressing the load. try 150 and 200 thousandths off the lands.

Gary

Hi Gary.
Well I seated some to .100 off the lands. Group opened way up. Did not try any seated deeper then that.
The best groups seem to be with the bullets right in the lands...not sure if I should try seating them deeper in the lands??
Right now I can open the bolt and remove the round without it pulling the bullet out of the case. Would you suggest jamming as my next step?

Also...I FL size...would just kneck sizing help with this?

Thanks for your time.

 

[Innovative]

BigBamBoo .......
I ran into the same thing with a rifle that would normally shoot half MOA groups all day long, then I started getting 1 or 2 occasional flyers in some groups. I measured my handloads back from 'low on the bullet ogive' to the base of the case, and I found surprising variations. Those bullets were all seated with the same press, the same seating die, and the same setting.

Then I pulled the bullets, and made the same measurements on the bullets alone. I found the ogive to not be consistent on all of the bullets. They looked fine, but they measured quite different. When I culled out those bullets the problem was solved.

I used our Digital Headspace Gauge to do the measuring. This gauge is designed to display the exact clearance that YOUR handloads will have in YOUR particular chamber,at the shoulder). However, it will ALSO measure your bullets back from the ogive. This exposes inconsistent seating depth and irregular bullet shape.

I'd look at this, and see if it's your problem. You can see this new digital gauge that I used on our website below.

- Innovative

 

[BigBamBoo]

Interesting. I do use a comparator and go through my bullets and make sure the ones I am loading with are very close to each other. And I seat the bullets using the ogive not the tip of the bullet.

It has me stumped.

Take care

 

[cliffy]

Random erratic accuracy problems are created by velocity deviation. What is you chronograph telling you? Example: my Lapua 105 Match loads can cover an entire bullseye with the wrong powder and grain load. My chronograph showed 125 fps velocity deviation, and way too low,2750 fps) velocities with slow-burn powder. I used too slow-burning of powder for my accuracy expectations. Hodgdon did not make and perfect H4350 powder for no innane reason. Bring your loads up to 2900 fps muzzle velocity and realize the greatness your .243 can perform AT! cliffy

 

[bheadboy]

I had the same problem with a 260 AI, i suggest you do two things, reduce your powder load 5-10%, seat on or just off the lands, and check the water volume of your fire formed cases vs a factory case, calculate the %increase and load no more than that % higher than max loads from Sierra or Hodgden for std 243.

AI's aregreat but can be overloaded easily

bheadboy

 

[jlmurphy]

I cured a similar problem by switching to collet sizing. I was full length resizing and I think the neck tension was inconsistent, there is also the issue of the neck brass work hardening. I have been using the LEE collet die, relatively inexpensive if you can find one. I have a Savage Target action, Hart barrel 1/8' twist in .243 Win., in a McMillan A5 stock. After collet sizing the first four 3 shot groups were 1/4'. I'm not that great a shooter, I quit looking for a better load. This was with Re 22 and SMK 107s at about 3050 fps, seated .010' off the lands.