Problems getting a .338RUM to group

[Randomshot]

I have been trying to work up a load for my .338 RUM. I've gone through 3 different powders and two different weight bullets. The best combination I' ve found so far is a Barnes 210 grn ttsx being pushed by 95 grns of retumbo lit by a fed 215m gold metal primer. This load averages between 1.25 - 2.5" groups which is far less than this round is capable of. When I check the bullet seating depth on the gun I found it is 3.84" I tried to back the bullet off .05 to 3.79" . When I checked this in the gun it is nowhere near fitting into the mag well. So I loaded to the gun which is 3.68" and this is what the above listed groups were from. Checking the book Barnes recommends a COAL of 3.6 I was thinking of loading to this but that would place the bullet .24" off of the lands. So now for my questions has anyone had any luck using this much bullet jump? I'm at the point now where I feel that I'm throwing good money into a bad gun and am at the point of sending the gun out to have it rebarreled so any advice or insight will be appreciated.

 

[Lungpopper]

Not sure how for off the lands my loads are ,but I had to do the same thing. I switched from ballistic tips to TTSX and they wouldn't fit in the mag well. So I loaded to fit the Mag well. Don't remember how far but still getting 3/4" groups. But mine is a Win mag.

 

[NBK]

The Barnes do not shoot well when close to he lands. I have been shooting the X bullet since 1989 and one thing I have learned is to seat the bullet much deeper than I would with a traditional lead core.

My buddy shoots a 338 RUM and has had good luck with Reloader 25. Snake Charmer has played with the round a bit and has had good luck with a Rem model 700 mountain rifle. He did not get the max velocities but I believe he got good accuracy. I am sure he will chime in or you could PM him.

 

[Randomshot]

I'm shooting a 700 as well and have tried RL 25 and 22. I also have been shooting triple shocks for years and never have had any issues with them before. With the retumbo power I worked up loads in half grain increments through the listed range and got the best groups at 95 grains. I'd figured I would tighten my groups with playing with the bullet seating but still am not happy with my results. I loaded another 40 rounds at different seating depths which I plan to test on Monday. Hopefully one of the loads work or I may be shipping this one off to Hart for a new barrel and some action trueing.

 

[Snake Charmer]

I've worked with the 338 ultra quite a bit, The load I developed uses the 210 Barnes with Federal 215 match primers and reloader 25, I'm getting just over 3000 fps at the muzzle and it groups at right around an inch give or take. I think you are on the right track I suggest you start with the lowest recommended amount of powder and work your way up a grain at a time. The bullet seating I used was the recommended overall length so I didn't play around with the depth too much. The other thing I did was use a lead sled to dampen the recoil as this round can really belt you when you pull the trigger. I don't know how recoil sensitive you are but you should consider whether you are flinching, I know when I have worked with it in the past I limit my shooting to nine rounds per session (three three shot groups) because I have found that any more than that I start anticipating the gun going off and my groups get larger. Also make sure everything on the gun is torqued to the proper specs as the recoil is pretty brutal and can make things shift.

 

[Randomshot]

I've worked with the 338 ultra quite a bit, The load I developed uses the 210 Barnes with Federal 215 match primers and reloader 25, I'm getting just over 3000 fps at the muzzle and it groups at right around an inch give or take. I think you are on the right track I suggest you start with the lowest recommended amount of powder and work your way up a grain at a time. The bullet seating I used was the recommended overall length so I didn't play around with the depth too much. The other thing I did was use a lead sled to dampen the recoil as this round can really belt you when you pull the trigger. I don't know how recoil sensitive you are but you should consider whether you are flinching, I know when I have worked with it in the past I limit my shooting to nine rounds per session (three three shot groups) because I have found that any more than that I start anticipating the gun going off and my groups get larger. Also make sure everything on the gun is torqued to the proper specs as the recoil is pretty brutal and can make things shift.

It isn't a recoil issue I have an answer brake on the gun and with it the recoil is less than a 7 rem mag without IMO. For a rest I'm using a Caldwell rest and have never had a issue with it before. My biggest issue with shooting it in fact is cooling time for the barrel. That being said Snake Charmer have you ever checked your gun for the OAL vs the COAL your loading at? I loaded some rounds at the COAL recommended by the book but just can't see how loading a quarter inch off of the lands can improve accuracy. Everything is tight on the gun and it has a Burris black diamond scope with lapped rings and has been marked for movement so that doesn't appear to be the issue. Thanks for the comments though I'm just curious if Remington over reamed the barrel at this point. It is a left handed gun and was a limited production run (and no the bolt being on the wrong side is not the problem just in case anyone was thinking it).

 

[TopBuck]

No advice for the 338 Rum, but my son has a 300 Rum and we had major problems working up a accuracy load, after tons of $ and lots of time it ended up the gun came from Remington with - zero head space! Sent it back to the factory and they fixed it plus did some extra stuff for free. You may want to have a gunsmith check it out?
My son and I went to a gun shop yesterday here in Albuquerque and walked out with a weatherby 338/378 mark 5, holy smokes what a cannon! I think he's gone crazy!

 

[NBK]

Not high jacking the thread but here is some interesting info on the 338/378 -

The barrel life of expected decent accuracy is around 600 rounds. After that, barrel erosion takes over. It is a true 1000 yard gun but is somewhat punishing to say the least. I guess anything with over 5000 ft pounds of energy is brutal no doubt.

Below speaks for itself!

Weatherby factory ammo, has a 225gr Barnes TSX moving out at 3180. Holy smokes!

 

[NBK]

John -

How many shots have you fired through the gun (overall)?

I did some reading - The round (both the 338 and the 300 Rum) have accuracy challenges and are known to be finicky. The three popular powders are H1000, Reloader 25 and Retumbo. You probably knew that. Everything I read was just a validation of what I know about the cartridge already.

It may be advantageous to do a chamber casting. If the results are what you have described - it needs to be sent back to the factory. I can help you with both if you wanted. Chamber casting will answer the question as well as validate the need for Remington to step up to the plate.

Just some thoughts

 

[Randomshot]

I took it to the range today and test shot it at some different seating depths. The book COAL was entirely a waste of time and was a huge step in the wrong direction. The bullets I loaded at 3.79 produced good results as can be seen below. Now the problem is unless I want to only use the gun as a single shot this load will not work for the magazine depth which will allow for a 3.68" OAL

The picture on the right had a flyer due to being rushed for a cease fire and shooting with the barrel still hot. Figures the last shot of the day and it ruins an otherwise good group.

 

[Lungpopper]

Try a different bullet, something like the Nosler E-Tip. Or your going to have to get it re chambered.

 

[Randomshot]

Try a different bullet, something like the Nosler E-Tip. Or your going to have to get it re chambered.

I loaded some old nosler 230 grn failsafes and had poor results with them but to be fair I only shot one load. The Barnes bullets are pretty long being all copper I planned to give the 225 ttsx a whirl before I give up and send it out. I'm hoping that a longer bullet may help the seating issue.

 

[NBK]

You may still run into magazine challenges though.

 

[Randomshot]

I know but I was thinking of going to 225 anyway so at least I'll have components ready for when it comes back.

 

[scohen]

After I saw your last post what I'm writing here may no longer apply to you but may help someone else with similar problems.

Let me change the approach a little here..... What kind of stock you have on that rifle synthetic or wood? Is the barrel floated and is it bedded? How heavy is your trigger pull? How hard is the surface you're resting the rifle while making those shots? How close you shoot your next shot when checking for accuracy do you leave the barrel to cool down after every other shot? Some times after the 3rd shot some thin barrels tend to get hot and loose accuracy.

I think both a perfect load and a tune-up rifle make the perfect combination....

Take care

Papi

 

[Randomshot]

I put a HS Precision stock on it which has a full length aluminum bedding block and was bedded. The barrel is free floated to the recoil lug and the trigger pull is set at 2.25 lbs. That being said the scope bases are also bedded and the rings were lapped. I am using nosler brass which comes weight sorted but also has been neck turned and cleaned with an ultrasonic cleaner between each firing. I use A RCBS loadmaster for my powder measuring which is good to .1 grn. The firing today was done from a stable shooting bench and I allowed what I feel is sufficient cooling time between rounds ( my rule of thumb is if I can't hold my hand on the barrel I do not shoot it) so I feel I have those bases pretty well covered but like you said Papi it may help someone else. Most time I'm on the other side of this conversation trying to give advice to others. Non free floated barrels and loose action screws seem to be the most common problems I see at the range.

 

[Lungpopper]

Have you tried a TSX? I know it's less BC but being a little more rounded without the polymer tip it will get you closer to the lands.

 

[Snake Charmer]

Random, Some back round on the load I developed, The rifle is a custom shop model 700 in left hand I developed the load for a friend, I used once fired Remington brass that was neck sized and trimmed to just under max length, I don't Have the reloading specs in front of me as I gave all the data back to the owner. Normally I use a Hornady loc n load chamber gauge to determine bullet seating depth, because I didn't have the proper brass to use the gauge I seated the bullet long in a test case and kept seating deeper until I could close the bolt I then backed it off .030 further. that still wasn't short enough to fit the magazine so I ended up using the magazine length to determine max bullet seating depth. I have run into this quite often, the manufacturers puts so much free bore in the chamber that you cant seem to seat at the depth you want. The photos you showed of your groups look respectable but the single shot feature isn't an option. I suggest you try what I did with max length allowable in the magazine. A chamber cast would tell you volumes.

 

[Randomshot]

Snake Charmer I used a RCBS precision mic kit to determine the OAL. The 3.68" OAL that I was getting poor grouping with was based off of what the magazine would accept. The gun basically has .16" of free bore between what the mag can accept and has to be loaded at to be used as a repeater. Do you remember how much play the gun you dealt with had?

 

[Snake Charmer]

Random, I don't recall but .16 is too much in my opinion so you may be looking at having the gun rechambered to reduce the free bore, As I said previously I have seen the excessive free bore thing in many guns I have worked with, I don't understand why they do this maybe its a safety liability thing.