Range day with questions

[Silentstalker]

Hey guy's,

Made it to the range today. It was a balmy 26 degrees when I pulled in. Slight wind at my back and sunny. Here are a few pics and A few questions. I think I have my 22-250 dialed in tight now. Still working on the 7mm.

Pic labeled Group 1 is my best 100 yard group out of my Rem 700 22-250 today. 50 gr. Vmax, 36 gr. varget, CCI BR primer, WIN brass. .463" group.

Pic labeled 7mm #2 is my best group today. 7mm Ruger M77. 162 gr. SST 73.5 gr. Retumbo CCI Mag primer. .966" group.

Pic labeled 7MM group is one I have a question about. It is inaccurately labeled as 73.5 grains. It was actually 73 grains of retumbo.

Of the 2 7mm groups you see here, which are the best 2 to tweak? the smaller group or the one with 2 bullets touching and a flier? For those willing, please tell me which group you would work with and what you would do to try to tighten it up. As you can tell I am fairly new to this but really trying to learn as much as I can. Thank you for your help so far!

Chad

 

[OU812]

Between the 2 I would work with the bottom group as I think it will come in easier than the top group. In doing so you need to seat the bullet deeper by a 1/4 turn down on the seating die, repeat until the group closes up, and it will.

On a different note you might try RL22 as it seems to be the cats azz in the 7mm with 160'ish grain bullets.

 

[HTDUCK]

Bottom target.
Duplicate that load twice more and go shoot it again just to be sure it wasn't operator error.
If that doesn't pan out start playing with seating depth.
Also another nod for RL22 in the 7RM and 160s

 

[Silentstalker]

Sounds like its the lower group then. I will load up two or three sets of three of that same load. If the group stays the same i will mess with the seating depth. Both of these groups were seated to 3.290

Just a follow up question or two. This is my 1st time adjusting seating depth. So far all i have done is loaded to max coal. How many 1/4 turn adjustments would be typical in searching for the sweet spot and how deep is too deep?

Sounds like i better find some RL22 also.

 

[HTDUCK]

You need to realize that seating depth can be adjusted two ways.
Shorter OAL or Longer OAL .
Some barrels have a long throat in them.
Long throat means you can move the bullet out, OAL is longer as long as it runs through the magazine you are good to go.
Your rifles magazine will determine how long or short you can go.
Get a tool that is designed to find the maximum length you can load to or you can take a case and a bullet and find this number with little effort.

I can explain a method of doing this without the tool. It's not complicated, but lengthy.
PM me for details.

Howard

 

[OU812]

Here's the deal.

If you shoot a 3 shot group and it's an equilateral triangle you need to seat the bullet out by 1/4 turn and try again until either the group shrinks or you run out of mag box length.

If you shoot a 3 shot group and 2 touch or darn near but the 3rd shot is out you need to seat the bullet in 1/4 turn at a time til the group shrinks.

The above is not a 100% guarantee but if you are using a powder well suited for the caliber and a bullet/weight that the rifle shows signs of promise as in your case, these 2 methods do work.



I always start my loaded rounds COAL at the max mag box length that will allow the rounds to fit in the mag box and still feed properly. Once I have found this length (I use a dummy round to do this) I chamber the round. If it fits and the bolt closes then the bullet is not contacting the lands and am good to go. If the shell will not chamber, bolt won't close, then this shell length COAL is too long and bullet is hitting the lands. Seat the bullet deeper til it will chamber and back off a little more. By using this method I don't have any room to seat the bullet out cause my mag box won't allow it, but, knock on wood, it's always worked so far with great accuracy in many many rifles.


You would do very well to locate some RL22, it will be your friend in the 7mm with 160 bullets. If the search function here didn't suck so bad you find lots of 7mm and RL22 info. RL19 isn't a bad choice either if RL22 can't be located.

 

[Silentstalker]

Great info. I will give it a try. Thanks!

 

[OU812]

Great info. I will give it a try. Thanks!

Keeps us posted with your progress. Other powders to consider IMO would also include IMR7828 or H1000.

Might even try Fed 215 primers if you have some or can get a few. If you do this back off any load at or even near max because changing any component can cause pressure spikes. If any doubt always start low and work back up, it's the safest way and you just might find a very accurate load in the process.

 

[SJB358]

I am with the others, work with the bottom group and like Bill mentioned, a 1/4 turn on the stem each time and I think you will have a bug holer.

RL22 is an excellent powder for 160's and 175's, but Retumbo doesn't look bad at all either. Good luck, looking forward to seeing your final groups.

 

[Polaris]

I'm gonna catch flak for this, but you really don't have enough rounds downrange to make any informed decision about your groups. They both show potential, both show potential weaknesses.

Depends on how your rig and load react to increasing fouling and heat.

I do not make any decision on load develpment without at least 2 5 shot groups as a starting point. Goes with the monkey at a typewriter theory regarding random probability. 10 shots would be better to rule out accidental good groups, but is not really practical. I think 5 is a good compromise number. 3 shot groups are false economy. You will pursue some bad loads and rule out some that would print quite consistently with 5 rounds because it looks like it threw a flier where the next 2 might have straddled the flier and the 2 touching.

If your purpose with the 7mm is simply making an effective hunting load to 300 yards, you could go with either for further testing.

 

[CatskillCrawler]

I'm with Polaris on this. I'd shoot them both again exactly as they are and also adjust OAL +/- .015" and .030" for both.

 

[OU812]

I agree with re-shooting the groups without making any changes to see if it duplicates. If it does then make the seating adjustments. I'm also of the school of thought that rather than a 5 shot group for big game rifles would rather see 3 3 shot groups with identical targets and aiming points then over lay them, but that is just me and how do it.

 

[Silentstalker]

I will definitely shoot these exact loads again and tweak them if they show repeatability. I have always done 3 shot groups. I do see the value in multi shot groups too. As a matter of fact thats what i have been doing with my 22-250 once i found my repeatable load. Thanks again for all the help. Im learning more and more each day.

 

[Silentstalker]

I am going to check the lands tomorrow and reload for my next session. I also picked up some berger 168 gr. hunting bullets. I plan to load the bergers at .010 from the lands to start with. Then use bergers seating depth adjustment recommendations with the most constant load.

Are there any real rules of thumb for the AccuBond or Partition as far as seating depth? Do they prefer a certain distance from the lands?

All of my previous loads have been to 3.290"

 

[velvetant]

With my limited experience with the NAB it likes to be seated deep, My .270WSM likes .100" off the lands and my buddies 300WSM likes them .075" off the lands.
From What I read on this forum others are also seating them deep for best accuracy.