Help on understanding bullet patterns

K9 Stalker

K9 Stalker

New member
Last year I read a post on understanding bullet patterns, and can not find it to save my life. Unfortunately, I have lost a lot of data and ref material that I had accumilated over the last few years.

This is what I need to know. When working on starting loads, someone had written a great post on relating the bullet pattern to seating depth and charge. As an example, if your 5 shots run a diagonal straight line Vs an arc, or a triangle. I haven't work on any new loads in a long time, and I have a 22-250 that is giving me some grief.

Win brass, WLR primer, V-max 55gr, H380 @ 37.8 seated .035 off the lands produces a 1" group that is a diagonal line running on a 45 degree angle from right to left.

The exact same pattern is also produced (near perfectly) with the change of the charge increased to 39.0 with a seating of .045

If I decrease the charge, and move closer the lands, I get the same result, but not improving the pattern.

Running the same load info, but going to a CCI and Fed 210M primers, I get a "box" pattern with increased pattern size.

I have been increasing/decreasing the bullet seating in .005 increments with a constant beginning charge. Once I have the best pattern with a seating depth, I run the charge in .5 gr increments to get the best pattern. From there, its small tweaks for improvements.

I'm in a rush because of work and lack of time. I have 2 days left to get a reasonable working load for a p-dog shoot. The post I had read did a great job of explaining the relationship of the bullet pattern to what is going on. Made it easy for adjustments (faster, slower, bullet not stabilizing....)

Can someone help?
 
Try a different powder.

I had horizontal stringing in my 270, using RE22 and a 130 Barnes TSX (3,200fps though). I changed primers, tried DWM, Remington and Winchester brass and changed seating depth. I even Dremeled out the old bedding and re-bedded the rifle, with no change.

I switched to H4831sc and IMR4350 and got great accuracy with NO horizontal stringing.
 
Originally Posted By: K-22hornet.Try a different powder.

I switched to H4831sc and IMR4350 and got great accuracy with NO horizontal stringing.

I have had awesome success with the H4831SC with Barnes bullets. I shoot the TSX 130 gr in my .270. Tack driver at 300 yrds
 
What twist is the barrel ? Mine does the same thing with the 55gr . Mine will shoot .345 @ 100 with 52 gr FBHP or BTHP I use 380 powder also 38 gr with CCI lr primers
 
With a 14 twist, I would try a 45 or 50 grain bullet and switch powders. Varget and RE 15 are huge modern favorites and IMR 8208 is a brand new powder that is gaining popularity. Personally, I have a 12 twist so I shoot 55's and pretty much all of them shoot well over the aforementioned powders, but 8208 is my go to powder and a berger bullet. I think your biggest problem is that 14 twist barrels can be finicky about heavier bullets.
 
Some of the guys that I know who have shot the 22-250 since it was a wildcat round, told me many years ago that if you are have problems making a 250 shoot well to try putting rubber between the very tip of the forend of the stock and the barrel with a slight amount of up pressure on the barrel. This usually settles them down, it has worked well for me. Depending on how your barrel is floated [it is, isnt it?] you can use inertube or on some I have used bungee cord cut to fit. It wont alter the gun so if it doesnt work just take it out, but I bet it will help.IMO
 
Originally Posted By: horsedrWith a 14 twist, I would try a 45 or 50 grain bullet and switch powders. Varget and RE 15 are huge modern favorites and IMR 8208 is a brand new powder that is gaining popularity. Personally, I have a 12 twist so I shoot 55's and pretty much all of them shoot well over the aforementioned powders, but 8208 is my go to powder and a berger bullet. I think your biggest problem is that 14 twist barrels can be finicky about heavier bullets.

I've heard this before, however, the factory loads of Hornady 55gr V-Max is what it liked the best. Extremely impressive groups for factory loads. Much better than the 50's. Since I shoot so much, I want to get a hand load dialed in for it that matches or exceeds the factory loads.
 
I'd try dropping the charge and working up. All the speed in the world doesnt mean crap if you can't hit what your aiming at. Also try different bullets. You didn't say if your using a fb or bt bullet. My 2506 will shoot the crap out of a flat base but I have to work with the boat tail in it, again that's probally just a charge problem though also. Good luck
 
Hey, thanks for the suggestion on going to Varget/changing powders. After all the grief, I couldn't believe how fast (almost by accident) I found a load to use.

Took the best of bullet seating depth and approx bullet speed from the best H380 load pattern and made up 9 loads to try with Varget that book wise was similar.

3 bullets - 1 hole, and an odd ball. When I pressed the bullet in on one, it didn't feel right. Just a little more resistance than normal. So, I took a sharpie and marked the brass to see if that shot would be different - It was. As always, appreciate the info here and everyone that is willing to give good info. Can't wait to crono it see what it's really doing. But I'm sure a p/dog or coyote won't notice a few fps difference!

Howa 1500
Burris XTR scope
22-250
1:14 twist
V-Max 55gr
Varget 35.6gr
Fed 210M primer
Win Brass
Guessing about 3500fps
22-2504shota.jpg
 
I have great accuracy with 36 grains of Varget and a 52 grain Berger in my 22-250. Rifle is a Tikka Varmint.
 
Last edited:
Originally Posted By: lazy1What twist is the barrel ? Mine does the same thing with the 55gr . Mine will shoot .345 @ 100 with 52 gr FBHP or BTHP I use 380 powder also 38 gr with CCI lr primers

In my Savage 10 26" 1 in 12" barrel I get .75" groups at 200yds. This is a magical load.
 
Looks like you found the majic load. Your right, seating tension should be the same for all loaded rounds. If not you will send flyers to and fro.

Tom
 


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