Long range load development at 100 yards.

[trailrider121]

Looks like -.019" is the one! Nice shooting!

That's what I figured. I was just waiting for your response. Thanks for your time, and your postings. Donation made to the site!

 

[Budget]

Hi Erik,
Many thanks must go to you on this thread,very helpful.
I have a question for you please. I am a fullbore target shooter from Australia that can't stop trying to find the ultimate group and certainly willing to try anything.as you are properly aware we use open peep sights . I have previously tried group shooting at 100 yards before but dismissed this test because I thought that I couldn't determine the data because all shots virtually key hole one another.
I then started reading your thread and thought I may revisit it again. My problems that I face that I hope you could shed some light on are.
1/ we must use 155 grain projectiles
2/ our know speed for 1000 yds must be between 2995- 3000 fps ( to stay supersonic)
3/ to get to that speed you have to have 45.8- 46.0 grain of varget
4/ my barrel is a 1/13 300 / 3075 30 inch.
4/ projectiles are either berger full bore 155.5. Or Sierra 155.5

In America they seem to have a little bigger window ( 46.0- 47.0 grains powder) but here in aus we don't seem to push them so much.
So given the data supplied how do I go about 100 yd testing and determining any successes with such a small window.
My rifle off the sling is capable of 1 minute of angle @ 300 yds
Any help is much appreciated
Kind regards Paul

 

[Erik Cortina]

I'm sure you mean you need to be above 2,995 fps.

I would not let other shooters loads determine the window for your load in your rifle. I would load from 45.0 gr to 48.0 grains. Make sure you stop the minute you see pressure signs if you encounter them. This will isolate your node.

Good luck.

 

[Joe Maisto]

My consensus with you Erik on accuracy load. Would you recommend adjusting seating depth at 100 yards or move it out to say 300 yards? More pragmatic at 300 yards would be best and give better feed back on what the load is doing. If 300 yd not available, the 100 yd would work with careful examination.

I used to do the seating depth at 300 yards, but now I do it all at 100 yards since I have found that if it shoots well at 100, it will shoot at 300.

+1

 

[Budget]

Hi Erik ,thanks for replying,good pick up and yes anything above approx 2985 fps is good to go.
45.0 of varget is never going to cut the mustard,too slow. 48.0 grains of varget too dangerous.so the load window knowing the speed of a thirty inch barrel is going to be approx. between 2980-3000 fps. So given the data as we know between 45.7 - 46.2 can your theory still work using 155 grain projectiles at 1000 yds.

Regards Paul

 

[Erik Cortina]

Hi Erik ,thanks for replying,good pick up and yes anything above approx 2985 fps is good to go.
45.0 of varget is never going to cut the mustard,too slow. 48.0 grains of varget too dangerous.so the load window knowing the speed of a thirty inch barrel is going to be approx. between 2980-3000 fps. So given the data as we know between 45.7 - 46.2 can your theory still work using 155 grain projectiles at 1000 yds.

Regards Paul

Accuracy doesn't discriminate against bullet weight. The only issue would be the narrow window you are willing to test. 20 fps. will be real tough to land.

I did not suggest you shoot the 48.0 load, I said to load that high and shoot until you experience pressure signs. It may be higher than you think it is.

 

[nmibex]

Erik, thanks for this thread.

How do you choose the starting load for a cartridge and bullet combination you don't have experience with? 4 grains under the max in a load manual?

Thanks,
Dick

 

[Erik Cortina]

Erik, thanks for this thread.

How do you choose the starting load for a cartridge and bullet combination you don't have experience with? 4 grains under the max in a load manual?

Thanks,
Dick

10% under max.

 

[finnaddict]

Went to the range again this a.m. after making some small adjustments to the stock fit. It is a Bell and Carlson Medalist. The barrel was making contact during the last range trip. Fine dust could be seen on the outside and under the barrel when I removed it. Now I knew why such large POI spreads. So that was sanded down as recommended by the Bell and Carlson website. What a big difference to be seen compared to the last outing.

Any input would be appreciated about the target results. I think I know which to go with but wanted to hear from some of the experts to be sure I am on the right track. A 2 MOA elevation change was made to lower the POI so they would stay on paper starting with group 7. That I may not do next time because it didn't really seem necessary

Thanks in advance.

 

[savageshooter86]

I would try 41.5-42.5 again but don't make a scope adjustment. Would also go in increments of 0.3 gr vs 0.5 this time around.

Then work on seating depth

 

[ricknot]

Hey Erik. Great thread. I thought I had this figured out but but after I shot yesterday and looked at my targets I'm just not sure. Looks like it could be any of them. If you could help that would be great. It was like 40 degrees and 8-10 mph wind and I think some of my shots were off a little cause I was cold and shaking LOL.

 

[daniel brothers]

Man O Man... what a thread.... AWESOME

 

[Erik Cortina]

Ricknot, I like 41.5

 

[ricknot]

Thanks Erik for the reply. Could you tell me why you think it's the best because I don't see where the MV had flattened out like you were talking about.

 

[Erik Cortina]

Thanks Erik for the reply. Could you tell me why you think it's the best because I don't see where the MV had flattened out like you were talking about.

41.5 and 42.0 have one shot where speed overlap. 2837 and 2834

 

[ricknot]

Ok great thanks. I hope I can figure this out on my own from now on. It's so good of you to help so many out.

 

[langenc]

In 22 Benchrest you dont want any verticle. If you still have some the BARREL needs more tuning.

 

[trailrider121]

Guys I'm a believer in Erik's method. I made a donation for all his work, and time he has provided in this thread.
My 260 is tack driving (for me anyways) those 130 Hunting VLD's. I'm just recreational shooter, and hunter. I stretched my 260 out to 700 yards Friday, and got a nice 5-shot group around 3-4". We can't go out to check the plate , so took a picture thru my scope.

Plate on the right with 5 shots in center. Also shot round plate on the left later that day with 5-6 mph winds.

link: http://i6.photobucket.com/albums/y212/trailrider121/308win%2020/b7b85e47-6b0e-40fe-aa42-b61ee3617ac8_zps394a5e90.jpg

http://i6.photobucket.com/albums/y212/trailrider121/308win%2020/8f5dc5d9-7186-45a8-908e-f8ff7b77820d_zpseb5e1f98.jpg

Here is my 7saum at 700 yards as well. 6 shots on small left plate, and 6 shots on right plate center right. 2-3 mph winds. It's holding vertical very well.

http://i6.photobucket.com/albums/y212/trailrider121/0207140937_zpsd80e5769.jpg

 

[eric32]

If you can work a spreadsheet plug in all the number and make some sort of line chart or bar graph to help you visualize the flat spot

 

[TZaun]

When doing this kind of load development, is it a big deal to sort bullets by length and weight or doesn't it make that much difference at 100 yards? Has anyone shot their sorted out bullets versus the "junk" bullets to see if makes POI or ESs change much?