Rem700 300WM Troubleshooting

[EarlYoung]

I'm newer to precision shooting than some and am having major stringing issues with a 300WM rifle built for me by a well known gunsmith in my area to use on a hunting trip that I was just barely able to "finish" in time to take. What I took with me had some issues that I needed resolved later, the trigger had a bind and I had set the torque value too high (65lbs I thought was standard but I should have had ~43lbs for this stock!).

Before I corrected the rifle, I expected no phenomenal results and was getting around .75" MOA with 200 grain ELDX @ 2850fps and 1.5" with both with 212 ELDX and 190 grain ABLR using fresh Nosler brass, CCI primers, and H1000. The 212 grain was stringing diagonally while the 190 grains were all over the place.

The other day, after filing out for the trigger and torqueing properly, I had time to develop loads for all 3 using reloader 26 and seating bullets again .03 off the lands in fresh brass and shot them in 3 shots groups. I had a primer dud on one of the 200 grain ELDX and, by the time I shot it, I didn't have enough light to chronograph it but the two shots were within half an inch of each other. The 190 grain was even worse than it had been, and the 212 grain @ 2900 fps shot another diagonal group but this time 3" long!

I've accepted the 190 grain ABLR won't perform in my gun but I would love to shoot the 212 ELDX and have hope for it. In my experience, dramatic stringing is normally caused by binds in the stock but is it possible the problem is elsewhere that would result in such a large string and what would your next step be? I havent been able to find any binds now and the 200 grains shot okay regardless of a known bind.

The rifle:

-Remington 700
-26" Douglas custom contour sporter bull barrel
-McMillan Game scout stock matched to the barrel
-Timney trigger
-VX6 optic
-Bedded, fire-lapped, and blue printed by the gunsmith

 

[Canhunter35]

Just for clarity: The best load with the 212s is 3"?
Try adjusting ur coal with the 212s. Being a different ogive than the 200s they might like a different amount of jump.

 

[EarlYoung]

Just for clarity: The best load with the 212s is 3"?
Try adjusting ur coal with the 212s. Being a different ogive than the 200s they might like a different amount of jump.

That is correct. I thought of maybe bringing them closer to the lands (increasing COAL), but, forgive me if Im asking a dumb question, will moving the bullet 0.01" or even closer forward really do much toward fixing 3" strings? If I do, should I need to start over in load developing from the chance of the bullet making contact with the lands however small and over-pressuring? I'm already at the minimum COAL with the bullet being 0.03" off the lands if that's helpful.

I'm yet to start backing off powder in half a grain increments to see if my groups improve but Im not close to book max and I have no pressure signs.

I'm sure there are many possible causes for my results and I may not have the experience to know how significant a role each problem might be. Ive only been able to troubleshoot once a week for a while and will be likely for another month or more because of work so I've been researching when I can to make the best use of the time I get to spend at the reloading bench and range. It's all I've been able to think about everyday and it's been driving me just a little nuts.

 

[Axl]

I would take it right back to the well known gunsmith and let him have another go at it

 

[EarlYoung]

I would take it right back to the well known gunsmith and let him have another go at it

I was worried I'd need to do that, I hate wasting time and money on ammunition only to have to have the rifle reworked. If backing the powder off doesn't take me to sub-MOA quick I think I will need to but does anyone know if changing the COAL might still be worth it? I put a lot of pay-checks into making a rifle with good components and 3" strings sounds a bit ridiculous to me with the loads I've been using.

I want to add, the trigger bind might have been related to him installing the newer trigger later on, after he had already worked the stock to the gun, and he may not have checked afterwards.

 

[Barrelnut]

I think adjusting the jump is a good idea too. Berger has a method for this that quite a few find helpful. It is a good read and may help. Here is the link:
https://www.longrangehunting.com/th...-from-berger-vld-bullets-in-your-rifle.40204/

Also, I don't think I have ever heard of a smith "fire lapping" a barrel. The barrel should have been hand lapped from the factory and I would be wary of messing with that. I have fire lapped a barrel before and the results were less than stellar. You can actually ruin a barrel that way.

 

[Canhunter35]

What powder charges have you shot the 212s at? Just a couple?
If it shoots the 200s sub moa it'll shoot the 212s.
How I develop a load for a new gun is walk it up in 1gr increments with 3 shot groups to max load and with a long coal then once I find a node try .5 gr each way trying to settle it into the middle of the node. Then if I need to I adjust coal, trying to find a jump the bullet likes. I usually adjust by .02-.03" this is just an overview. But it sounds like ur outside the node with your 212 gr bullets although 3" is wide for a custom gun. My 300wby with the 212s never shot larger than a 2" group during load development.

 

[EarlYoung]

Ive decided I'll be bringing it back to the gunsmith to see what he can do first. I put a lot of pressure on him to finish before my hunt and that wasn't fair to him in building it. He's messaged me about the accuracy of the gun and it's going to be tough letting the man know how it's performing, he takes pride in his work.

I will take the advice of adjusting the COAL further, I've never brought a gun closer than 0.03" but if it may help it's most certainly worth trying. Barrelnut, my father expressed the same concern but the smith wanted to lap it himself and I caved in. Canhunter35, I've found myself going to an ideal velocity first, then shooting for groups going down but I may use your method in the future.

I'll report back how my revisited rifle performs when it's done.

 

[oldno7]

Adjusting your COAL will make a large difference.
I'm setting up 3 guns right now and COAL can take groups from 2" to 1/2" in a few .00x

 

[ohiohunter]

Get off the lands. Jump them 10, 15, 20, 30, 40 thousands. Then do a ladder test, personally I do not think you've done your due diligence before you take it back to the smith.

 

[Canhunter35]

I agree with Ohiohunter, work on your charge weight and get good groups. It doesn't matter what velocity the bullets travelling but where it's flying. The smith can't make your gun like to shoot 212s at 2900fps

 

[Shane Lindsey]

The 178gr ELDX liked alot of jump in my 30-06 FWIW.
Also the Berger 215s liked alot of jump in my 308, like .070".

Most of us, like you start out as close to if not in the lands when we start load development. I would be inclined to seat them deeper and see what happens before you give it back to the gunsmith.

I have been pleasantly surprised with one of my 300 WM, it's a short box Ruger, long jump if loaded to the mag box and it will shoot sub half if I do my part with certain loads.

 

[Capt RB]

First H1000 is the goto powder for heavy bullets in the 300 win. Rl 26 can make you pull your hair out till you get to the node. Then all of the sudden it shoots.
Load .010 off from 69-77gns in full grain increments of H1000. Use a bunch of colored sharpies to color the exposed bullets. Use a white target with a cross hair aiming point.
Once you see the flat spots in the ladder then play with the chronograph. You can fine tune the flat spot by going to .3 grain increments. Once you have the charge then play with seating. Alex Wheeler just did a nice thread on long range ladders. Worth reading. The ELD's have been quirky in the 30 cal by some accounts. I have no experience with them. I'd run a 190 serria just to see if the gun will shoot. That has to be one of the easiest bullets to shoot in a 300 win

 

[EarlYoung]

I didn't want to put dirt on his name because of how I rushed him and how great and helpful he has been putting my rifle first in line but I noticed an issue with the muzzle brake on my trip and today, after some research, I think I may have found a major problem. There are burrs within it that I believe may be causing pressure oddities on the bullet even if they're not touching the bullet itself. The smith had wanted to reblue the gun as I took it with me anyways so I will be knocking two birds out with one stone.

I cannot give jump to the bullet without violating minimum COAL at 0.03 but I can make them longer. Noting all of your suggestions, I intend to try seating my bullets closer and starting over with H1000. I look forward to finding out what the gun will be capable of.