A Tale of Two Rifles

[IdaRam]

Hi Folks,
In many things in life someone else has already fought the battle and found a few tricks of the trade that can make it easier on your wallet and your patience! I hope that the following story and information may be of use to my fellow hand loaders

Over a period of almost 40 years I've spent a fair bit of time and a lot of money developing loads for most of my guns. The most recent project has been a Winchester Model 70 in .375 H&H. A beautiful stainless steel rifle with a glass bedded HS Precision stock. This is my second rifle in that wonderful and iconic chambering and the complete polar opposite from my first, a Ruger RSM that went with me on my first trip to Africa. The two could not be more different! Kind of like an older child who never gets in trouble, gets straight A's in school and you just know is going to grow up to be an accountant
And then there's his little brother... God help us all!
He's only 5 years old the first time he gets caught kissing the neighbor girl. He throws rocks at windows, comes home from school with a black eye or busted lip every other week, and you wake up at night in a cold sweat 'cuz you just know he's going to grow up to rob banks and end up in prison. That's my Model 70.
But you don't give up on him because there's something about this kid, something just below the surface, something that is worth believing in.
I had been looking for a long time for two specific rifles, both Model 70's. One in .375 H&H and one in .416 Rem Mag. Alaska and Africa rifles. Stainless, synthetic all weather rifles to do it all everywhere. I'm still looking for the .416 by the way.
I ended up buying the .375 slightly used off Gun Broker from a gentleman in Oregon. The rifle had been listed a few times and never sold. It was more than I wanted to spend, but was everything I was looking for. The original plastic stock had been replaced with an HS stock and glass bedded by a respected gunsmith who does a lot of Model 70's and he had also done a trigger job. What the heck, it's exactly what I'm looking for and only a couple hundred bucks more than I was hoping to spend so I placed a bid and ended up with the rifle.
The rifle arrived safe and sound in perfect condition. The only blemish was a slight nick in the stock right at the front of the barrel channel on the tip of the fore end. The seller had pointed this out in the listing and the pics.
I took the gun apart and cleaned everything including a good deep cleaning of the bore to remove every trace of copper. Everything looked good and I was a happy camper. Time for a trip to the range
I had loads worked up for softs and solids for my RSM that I was very happy with, as well as a few boxes of Federal Premium 300 gr Trophy Bonded Bear Claw so I figured I would start there and maybe with a little luck I wouldn't have to do a lot of load development. Little did I know...
I bought a hundred rounds of new Norma brass and loaded up a small amount of each of the same loads I was running in my RSM.
The loads for my RSM are as follows:
Wait a sec, you know what's coming The disclaimer of course!
All loads listed are below maximum in all published literature I know of. They are safe in my gun. I make no representation or guarantee they are safe in any other firearm besides mine. Travel at your own risk! I assume no responsibility for anyone else's hand loads!

300 gr Nosler Accubond
70.5 gr Alliant RL-17 powder
CCI 250 primer
Norma brass
3.595" OAL with light crimp in cannelure
2400 fps from 23" barrel

(For small light skinned animals - I do not recommend the DGS bullet for Dangerous Game)
300 gr Hornady DGS
74.0 gr Alliant RL-17 powder
CCI 250 primer
Norma brass
3.530 OAL with light crimp in cannelure
2450 fps from 23" barrel

These two loads regulate at the same point of impact at 100 yards, which was my primary objective. I wanted a solid that shot same POI as my soft for use on small animals such as Serval and Caracal for minimum damage to the cape.
In all the bullets and loads I shot in my RSM there really wasn't a huge difference in POI.
Time to head for the range!

Also time for me to go mow the lawn!
To Be Continued

 

[IdaRam]

FIRST TRIP TO THE RANGE
Well, range day rolled around. I had mounted a Luepold VX-6 2-12x in Leupold QRW bases and rings and bore sighted the rifle. I expected to need a few fouling shots to lay down some copper before the gun would really shoot. I started at 25 yards to make sure I was going to be on paper at 100 yards. A bit of minor adjusting and I was hitting 1" low at 25 yards. Let's head for a hundred...
I started out at one hundred yards with the Accubonds in new Norma brass.
Groups were not very impressive right out of the chute, although after about 10 rounds things were settling down a bit.
A side note here, after putting close to 300 rounds down the pipe of this rifle I have found that it takes about 20 rounds of fouling from a completely clean bore to get this gun to shoot decent. Less than that and she just scatters things around.
The best I could do with the Accubonds was about 2" groups which surprised me because I have always had good results with Accubonds of all sizes. My RSM shoots half MOA or better with 300 gr Accubonds. 5 shot groups in the M70 with the same load were averaging about 2.5". Not really what I was hoping for so I switched to the DGS.
My first shot with the DGS was a no show on the paper. Hmmm, where'd it go? One more shot showed a partial bullet mark right on the very edge of the paper in the top right corner. Really?
OK, I'll aim at the bottom left corner and see what happens. 3 shots later showed a bit over 1" group pretty close to center of paper. Much better, but really that much difference in POI?
OK I'll adjust zero for those and shoot another group, 5 shots this time.
3 shots in about an inch, one that stretched the group out to about an inch and a half and a flyer. Well OK, lets shoot some factory ammo.
First shot Federal TBBC, an inch below point of aim and 3" left of the DGS. Hmmm, that would put it about 3" above and 1" right of the Accubond. OK, shoot a few more. The resulting group was the best yet at about 1.25". But 3 inches left and an inch below my solids. Not where I want to be. Ideally it would be about 1" directly above the solids allowing me to zero dead on at 100 for the solid and be pretty close to zeroed at 200 for the soft.
Looking for the positive, all three loads fed glass smooth from the magazine, pressures were fine and the gun is pretty pleasant to shoot. I like the HS stock and the trigger is pretty nice.
Back to the loading bench...

 

[CAustin]

Sounds like your having fun doing this and that is what matters!

 

[PHOENIX PHIL]

@IdaRam,

Not sure I can make an apples/apples comparison between your M70 and mine, but a few thoughts/suggestions:

1) My M70 loves IMR4350 with 300gr pills. North Fork, A-Frame, TSX being the ones I've shot.

2) What I found with my M70 is it likes to shoot 300gr bullets at the fast end..... 2500-2550fps

3) My experience with Nosler bullets in general is they like to be seated long, particularly the Accubonds. I've not tried them in my .375 but in all other calibers this is what I've seen. For example seat them to 3.36" in my .300WM M70 and they're lights out accurate. Come back to SAAMI length of 3.34" and I get results like you do.

 

[IdaRam]

LOAD LADDER
I'll cut to the chase and spare y'all the boring details
Years ago on one of the reloading websites, I can't remember which one, I discovered some info that has proved incredibly valuable to me over the years and I've used it often in load development. It's called a LOAD LADDER. Many of you hand loaders may already know exactly what I'm referring to. For those who do not, here's a somewhat quick and dirty run down.
I use this tool for a number of purposes including determining what bullets I might be able to get to shoot to the same point of impact. Also to identify the sweet spot where I am most likely to get the most consistent accuracy and smallest groups.
Another purpose I think this could be used for, although I have not tried it, is double rifle load regulation / development.
Here's how it works. We expect that as we change velocity, pressure, projectile, powder, primer, etc we expect the point of impact at a given distance is going to shift. Hopefully not as much as I am getting in my .375! So choose a bullet and load up 10 cartridges starting well below maximum and go up in a set increment for each round loaded. Example: If we believe 76.0 gr of a given powder is a maximum load with our bullet of choice, load 1 round at 67.0 gr, the next one at 68.0 gr, the next at 69.0 gr, etc, etc until we have 10 loaded rounds ending up at 76.0 gr for the heaviest load.
Next, load up 5 more rounds with a powder charge that is in the middle of the range. In this case 71.0 gr. These will be used for zeroing the rifle before we start shooting the "load ladder".
Head out to the range, preferably on a day with good shooting conditions. Make sure the rifle is reasonably zeroed with some or all of the 5 rounds we loaded in the middle of our range. This will also foul the bore in the event the rifle was cleaned and lay down some fresh fouling which helps to start out on a level playing field.
Let the rifle cool adequately and then start shooting your load ladder beginning with the lightest load first. I always shoot over a chronograph and record velocities of each shot on a pre-prepared data sheet. I also like to have a target identical to the one I am shooting in my binder on the shooting bench. After each shot I draw a dot on my target where the bullet hit on the target and label the dot 1,2,3... corresponding to the shot number. I like to do this because when you are all done shooting 10 rounds you are going to have a heck of a time remembering which bullet hole corresponds to which round. When you get home you can transfer the numbers on your actual target if you wish, or just keep both targets.
When done shooting the load ladder (10 rounds) we have the following info. What the load was, what the velocity of the load was, where it impacted the target, about how much velocity gain we get for each grain of powder increase, and a general picture of what increasing the powder charge/velocity does to point of impact. Some gun/cartridge combinations have very little point of impact shift as the powder charge increases, while others change a fair bit. Commonly, low recoil / high velocity rounds "walk down" as velocity increases. Also commonly, heavy recoil / lower velocity rounds "walk up" as velocity increases. It is also fairly common to see a bit of a diagonal string to the load ladder. As a load gets heavier the gun recoils more, but doesn't necessarily recoil straight back. The muzzle lifts and also shifts to the right under recoil for a right handed shooter, causing a bit of left to right as well up and down.
One of the things you are looking for are "nodes". A node is a shared or common point of impact amongst a number of different powder charges. For example, you shoot your first through fourth rounds and they show a string that starts to "walk up" the target and then rounds 5, 6 & 7 hit virtually at the same point of impact, then rounds 8, 9 & 10 start walking up the target again. You may have identified a "node" with rounds 5 - 7. More testing is in order.
A node is indicative of a load range where your gun is "happy". It suggests your most consistently accurate load is going to be in that range because regardless of velocity variation within that specific range, your gun wants to print them all in the same spot.
Obviously that is just a start. Time to go back to the loading bench
I won't belabor the obvious, hand loading for optimum results can be time consuming. If you don't enjoy the process and reloading is simply a chore, a means to an end so to speak, this might not be for you. But if you want to tune a couple loads to shoot to the same point of impact, this is a great way to start the process. You can learn A LOT with very little time, effort and money by using this process.
This is exactly what I did to find a solid and a soft that had a snowballs chance in hell of shooting to the same POI with my M70 .375 H&H.
I found that a 300 gr Swift A-Frame and the Hornady DGS were the only two bullets that I tried that I could make work. Actually, that's not quite true. I had some 300 gr Woodleigh solids on hand that shot great and very close to the A-Frames, but when I tried to buy some more they were sold out everywhere! None to be had. I would much prefer to shoot the Woodleigh's but what's a guy to do? They are shown on MidwayUSA as being back in stock at the end of June and I leave on July 4, so no dice.
It seems to me that employing this same strategy for double rifles may be very effective as well. I don't know, I don't own one. Yet!
If any of you double rifle authorities read this, I would love to hear your thoughts on the subject!
Anyway, I ended up with a combination of softs and solids that both shoot to same point of impact and print 5 shot groups of about 1" at 100 yards. Time to go hunting!

 

[IdaRam]

Thank you Phil. I've shot H4350 in both .375's and they both like it. It's a great powder and I use it in a number of other cartridges as well, including .30-'06 and .280 Rem.
I really think the barrel in my M70 may have some wierd stresses in it or something. It shoots reasonably accurately with a few different bullets, but I've never seen a rifle that prints different loads all over the map like this one.
I may try rebarreling it after I get back from this trip. Otherwise, I love the gun. The action is glass smooth and it feeds everything I have tried without a hiccup.

 

[IdaRam]

An example of a load ladder that walks up and to the left as the charge increases. Notice the tendency to cluster into "nodes". Shot #4 is a bit suspect. Obviously a rock solid rest, careful shooting and consistent technique are critical to the results.

 

[Dr Ray]

FIRST TRIP TO THE RANGE
Well, range day rolled around. I had mounted a Luepold VX-6 2-12x in Leupold QRW bases and rings and bore sighted the rifle. I expected to need a few fouling shots to lay down some copper before the gun would really shoot. I started at 25 yards to make sure I was going to be on paper at 100 yards. A bit of minor adjusting and I was hitting 1" low at 25 yards. Let's head for a hundred...
I started out at one hundred yards with the Accubonds in new Norma brass.
Groups were not very impressive right out of the chute, although after about 10 rounds things were settling down a bit.
A side note here, after putting close to 300 rounds down the pipe of this rifle I have found that it takes about 20 rounds of fouling from a completely clean bore to get this gun to shoot decent. Less than that and she just scatters things around.
The best I could do with the Accubonds was about 2" groups which surprised me because I have always had good results with Accubonds of all sizes. My RSM shoots half MOA or better with 300 gr Accubonds. 5 shot groups in the M70 with the same load were averaging about 2.5". Not really what I was hoping for so I switched to the DGS.
My first shot with the DGS was a no show on the paper. Hmmm, where'd it go? One more shot showed a partial bullet mark right on the very edge of the paper in the top right corner. Really?
OK, I'll aim at the bottom left corner and see what happens. 3 shots later showed a bit over 1" group pretty close to center of paper. Much better, but really that much difference in POI?
OK I'll adjust zero for those and shoot another group, 5 shots this time.
3 shots in about an inch, one that stretched the group out to about an inch and a half and a flyer. Well OK, lets shoot some factory ammo.
First shot Federal TBBC, an inch below point of aim and 3" left of the DGS. Hmmm, that would put it about 3" above and 1" right of the Accubond. OK, shoot a few more. The resulting group was the best yet at about 1.25". But 3 inches left and an inch below my solids. Not where I want to be. Ideally it would be about 1" directly above the solids allowing me to zero dead on at 100 for the solid and be pretty close to zeroed at 200 for the soft.
Looking for the positive, all three loads fed glass smooth from the magazine, pressures were fine and the gun is pretty pleasant to shoot. I like the HS stock and the trigger is pretty nice.
Back to the loading bench...

I suggest you try a different powder.
I've seen the same problem with a 243 I had.
Switched powders and groups simply shrank dramatically.
Originally I was using W760 and went to IMR 4350.
Also you may need to change primers too!
Just a suggestion.

 

[IdaRam]

Hi Dr Ray, thanks for the input.
I got it sorted out and have softs and solids shooting well and same POI.
I had the same thoughts as you've expressed, and I've tried RL-15, RL-17, H4350 and H414. Fed215 and CCI250 primers. Pretty much same results, although RL-17 and CCI 250's seem to work the best so I've stuck with that.
I think if someone had bought the rifle, dropped in factory Federal TBBC's, sighted in and gone hunting they might have never known or cared. The gun seems to shoot fine, it will print inch groups with many different combinations of ammo. It's just getting softs and solids to shoot same POI that has been the challenge.
Anyway, all's well that ends well!
Just thought I would share my trials and tribulations. Maybe a kernel of wisdom here or there can help other folks.