Question on Shrinking a Group

[Sekora]

I was able to purchase some N570 a few months back and finally had some time to work with it in my 300 RUM. The gun is a stock Remington 700 BDL other than a Sako extractor and a muzzlebrake installed. I am very impressed with the powder as it is giving me respectable groups with very good velocity, and low ES and SD well below pressure signs. I found a node that keeps the velocity around 3240, and shoots almost exactly the same groups from 92.7 grains to 94.0 grains. 93.3 seems to be have the lowest spread. All charges create a group of 2 almost touching, and one about a half to three quarters of an inch off. They are all grouped at an upward right to left group at about 45*. If I can pull the flier in a bit, I will be very happy with the gun and the load. I am loading to mag length as this is a hunting gun, so I am starting at -.150" off the lands. Would you guys recommend seating the bullet deeper first or changing primers? I have 2 other options of magnum primers I can explore. If seating deeper is the next step, what increments would you start with? Also, this is 3 times fired Nosler brass, so after this firing, I may be able to anneal, and trim all cases. Thanks ahead for your advice.

 

[David Christian]

@Sekora, play with seating depth. If -.150 is max mag length, load up 3x (-.155, -.160, -.165, -.170, -.175, -.180, -.185, -.190). See which one tightens up that flyer.

 

[natdscott]

@Sekora, play with seating depth. If -.150 is max mag length, load up 3x (-.155, -.160, -.165, -.170, -.175, -.180, -.185, -.190). See which one tightens up that flyer.

David, I like your comment, but bear in mind that this is an RUM we are talking about. Can’t be getting too crazy with the testing at one time before the shooter and barrel get worn out and hot.

I’d go with 10 off, 20 off, and 30 off, in 5 rd groups fired at no more than 1 rd per minute. Shoot them consecutively on 3 parallel bulls, with no break in position, etc. between.

If one of those tightens, and is round, then maybe split the difference to 0.005”.

At the end of the day, keep in mind that this is still an OEM Remington, and 1/2 to 3/4 MOA with fliers as they heat up is kinda par for the course.

 

[Dusty Stevens]

Its a factory rifle, and its a rum. Dont shoot too many rounds at a time

 

[dmoran]

^^^^^ I'll 2nd Dusty's input
3-shots per increment with cool down time in between is a great plenty from a factory rifle magnum - IME

 

[BoydAllen]

Playing with a custom .338 Lapua, we found that the same sort of issue came from a rear bag that was too hard, and in another case, moving the front bag back a lot and a different hold on the rifle yielded much better results. Essentially, we tend to approach all accuracy issues as if they are loading issues. When the recoil gets up to a certain level, relative to the weight of the firearm, sometimes changes have to be made in how a rifle is rested and held. The details are a bit more complicated. We can talk if you like.

 

[Rube Shooter]

I agree with everyone above. As for 3 shot groups, they are my norm when testing and give your barrel a cool down period.
Seating depth will give you an improvement, but my question is how are you increasing the amount of powder when you are testing? .1gr each load or more?

 

[msinc]

I'll take the "factory" thing one step further and say this...if you are able to touch two bullets at 100 and the third is 3/4" away.....I would run around in circles and j.......well, it's a Remington barrel. Seriously, exactly how good did you really think this thing should shoot??? Sounds like to me you got lucky, the last three factory Remington rifles I have owned/shot had trouble putting 3 into 2 1/2" at 100.

 

[Sekora]

Thanks guys. I guess I'm really lucky...all my remingtons shoot sub MOA. I got to shooting again today and am happy with the results. I found two good seating depths that I am going to revisit with the chronograph to see which one produces the lowest ES. I ran out of prepped brass and it was time to anneal, so I did all that. The annealing actually took the left to right out of my groups and I was then left with vertical spread. Most groups also had 2 touching, and one high. The two good ones were .650" and .750". The .750" was very little vertical spread and before annealing though. I think one more visit to the range and I will be done with this gun. I also always let my barrel cool between shots and the recoil is not bad at all with the brake. If I can stay under .750", I know I got a factory remington about as good as it gets.

 

[Dusty Stevens]

Most custom rifle builders will only guarantee .750 from a magnum. Youre doing good

 

[Rdlningcltchdmpr]

Listen up! Just stick with one magnum primer only. I use fed lr mag match. Next dont be afraid to go max on powder as many hunting loads are best at or slightly over max. Third , i had a rem. 700 - 300rum. And i had the same problem but luckily i figured out kwik that the trigger was dragging . that caused the flyer. I pulled the trigger off and put on my jewel trigger and just like magic perfect groups. Most shooters would not be able to detect a dragging trigger.

 

[Nick Caprinolo]

When using a hunting barrel, it will most usually get the first shot at point of aim. Second shot should be very close. If you fire the third shot in quick succession, the barrel will be pretty hot and a flyer is usually the result. This is especially true in Magnums. Wait 10 minutes and then fire the third shot and watch the improvement.

 

[Larryh128]

I was able to purchase some N570 a few months back and finally had some time to work with it in my 300 RUM. The gun is a stock Remington 700 BDL other than a Sako extractor and a muzzlebrake installed. I am very impressed with the powder as it is giving me respectable groups with very good velocity, and low ES and SD well below pressure signs. I found a node that keeps the velocity around 3240, and shoots almost exactly the same groups from 92.7 grains to 94.0 grains. 93.3 seems to be have the lowest spread. All charges create a group of 2 almost touching, and one about a half to three quarters of an inch off. They are all grouped at an upward right to left group at about 45*. If I can pull the flier in a bit, I will be very happy with the gun and the load. I am loading to mag length as this is a hunting gun, so I am starting at -.150" off the lands. Would you guys recommend seating the bullet deeper first or changing primers? I have 2 other options of magnum primers I can explore. If seating deeper is the next step, what increments would you start with? Also, this is 3 times fired Nosler brass, so after this firing, I may be able to anneal, and trim all cases. Thanks ahead for your advice.

A fan blowing chamber to muzzle helps greatly with cool down. I use a chamber fan all the time shooting suppressed, it does wonders.

 

[Brians356]

Playing with a custom .338 Lapua, we found that the same sort of issue came from a rear bag that was too hard, and in another case, moving the front bag back a lot and a different hold on the rifle yielded much better results. Essentially, we tend to approach all accuracy issues as if they are loading issues. When the recoil gets up to a certain level, relative to the weight of the firearm, sometimes changes have to be made in how a rifle is rested and held. The details are a bit more complicated. We can talk if you like.

There's always that quiet guy at the range who can sit down behind anyone's rifle and shoot a group half the size of the owner's best effort. A dose of instant humility but also raised hope knowing your load is not necessarily crap.

"Hey mister, can you tell me how to get to Carnegie Hall?"
-

 

[Sekora]

I had a rifle built by a well known local riflesmith and accomplished shooter a few years back. He explained to me the importance of a consistent hold on the rifle and how they ride the bags as they recoil, causing point of impact changes. Since I learned those things, my shooting has improved. I am not saying I am a great shot by any means, but I am asked frequently at the range to shoot other people's rifle and see if I can get a group. As far as the trigger causing the flier, I know that can be the case. My trigger is good for a factory trigger, but nothing like my Jewell. I know an upgrade would improve the gun, but I do not like the gun and do not want to put money into a gun I do not like. This is going to be strictly a hunting rifle for future trips out west for elk. I want to settle on a load so I can get my info to Leupold for a custom dial to be made. After I get to that point I may take the rifle out a few times a year to shoot long range. If it was matte finish, or stainless, I would probably change the stock and trigger, but it is blued. I do not like blued rifles. But, overall, I am happy with .75 MOA for a gun I don't like.

 

[Sekora]

I made my final load development trip to the range with this rifle this afternoon. I revisited my seating depth that had almost zero vertical with annealed brass. I tried two different primers to see which one performed the best. The winchester long rifle magnum primers gave me a .450" group with an ES of 8. This is shooting a 200 grain accubond at over 3200 FPS. I also tried another seating depth that showed promise prier to annealing the brass with the two different primers and the 215M's gave me a .641" group. The ES on that load was 25. I am going to give the gun a good cleaning now and put it back in the safe. It's time to move on to another gun! Thanks for the suggestions and hopefully someone reading this will learn something from it.

 

[Heavy Metal 1]

For hunting "out west" [I live in the West] you may want to shoot groups at 200 yds. I zero my hunting rifles to 200. At the speed your load is that should allow you to hold center of vitals out to 300 yds or so w/o trying to guess holdover. That works for me; of course YMMV.

 

[Sekora]

That is my plan, however there is a 100 yard range within walking distance of my house. I do all my load testing there as I can leave the range, make adjustments, and go back. After I find a good load at 100, I will shoot 200 - 400 and zero at 200.