horrible vertical stringing with 45-70 with RCBS 45-300-fn

[jhunter77]

My go to load is a jacketed hollow point with 46.2 grains of IMR 4198. I wanted to load up some of the cast 325gr I was given. I normally get sub 2" loads from jacketed with a 2x scope at 100 yards off shooting sticks. I have spent the day loading 5 to 10 rounds then going out back and shooting them looking at groups and trying again. I have gone from 34 to 43 grains of IMR 4198 and adjusted my seating up and down but keeping it in the crimp grove. For some reason all my cast groups will create anywhere from a 6" to 12" vertical string. They group horizontally between 2" and 5". Its obvious vertical stringing which I have not had issue with before with jacketed. I pull some of my old jacketed ammo out and proceeded to shoot a very nice 3 shot group that went into 1.5". I have tried regular Winchester primers and also magnum CCI. The rifle is a ballard cut marlin cb. The bullets are Clip on WW and fairly hard, gas checked, and lubed with Red Rooster lube. Suzed .458 or .459. I need to get a micrometer and verify it this weekend.

I have not slugged my barrel but will this weekend when I can borrow a micrometer.


What Could be causing this?

[Yodogsandman]

I'd start load development again and this time would use a tuft Dacron filler large enough to completely fill the space between the powder charges and the boolit base. Please read the sticky on "the proper use of fillers" first, just to be safe.

http://castboolits.gunloads.com/showthread.php?109280-The-proper-use-of-fillers

[jhunter77]

I could see the lower charges maybe needing the Dacron but the upper loads had the most vertical and the case was pretty full.

[chill45100]

How was the rifle rested? Have you found the sweet spot and marked that on the barrel? It sounds not unlike a problem I had on my .45-70. with resting the barrel on a spot that caused erratic vertical stringing. Found the sweet spot and marked that with blue painters tape for a consistent rest point. Use something like a plastic hammer and tap on the barrel every half inch or so until there is a noticeable change in the sound. When the pitch changes to a dull thunk that is the point that will be stationary when the barrel whips during recoil. Rather like whipping a fishing rod back and forth. There are placed that do not seem to move from the original position in space. Try this first and there is an improvement by all means see if Dacron will help even more. Could be a combination of barrel harmonics and velocity differences caused by the powder.
Just a random thought.
Chill4100

[Yodogsandman]

You were on the right track to try different primers. A wise member here told me that both vertical and horizontal stringing was due to ignition. It effects the barrel harmonics causing the stringing. Better ignition will tighten up the nodes of barrel vibration. Dacron will reduce the ignition variation caused by powder position in the case.

[chill45100]

Interesting information which I will remember. Had not thought of ignition variables too.
Chill45100

[Geezer in NH]

I would also try a bench and not a stick. Speed diff off the sticks may not be helping. And yes I shoot of sticks in NMLRA competition but the same light bench/buffalo rifle shoots better groups off the bench.

Get rid of the human factor first and try again. IMHO

[Larry Gibson]

To light a weight cast bullet for lower level 4198 loads. Even a dacron filler most often doesn't work. By the time you get the 4198 to ignite and burn efficiently the velocity will be to high for accuracy. I long ago switched to faster powders. I found Unique and Bullseye to be excellent choices for my own RCBS 300 gr and Rapine 460250 in my own 45-70s.

Larry Gibson

[jhunter77]

Thanks for the help, I will post back when I have tried a few of these and see what works best. barrel was rested on the wood stock and also held. Thanks

[MT Chambers]

For me that 300 gr. RCBS was/is too small for my marlin '95, and accuracy is mediocre at best, they passed a little bit too easily through my .459" sizer.

[knifemaker]

I have a Marlin 1895 LTD-V that will put 3 shots at 100 yards into 1 inch day in and day out. It will do this both with Hornady 350 gr. RNFP jacket and with a cast Ranch Dog 350 gr. gas check boolit. Because you are getting good groups with the jacket bullets, and not your cast tells me there is something wrong with your cast boolits.
The load I use for both 350 gr. cast and jacket is 43 gr. IMR-4198. Going up to 44 gr. started to open the group up. The big difference between my cast boolits and yours, beside the weight difference of 50 grains is that I size my cast at .460. If I size smaller, the groups open up. Most 1895 Marlins I have seen prefer .460 dia. for better accuracy over .458 or .459.

[MBTcustom]

I have a Marlin 1895 LTD-V that will put 3 shots at 100 yards into 1 inch day in and day out. It will do this both with Hornady 350 gr. RNFP jacket and with a cast Ranch Dog 350 gr. gas check boolit. Because you are getting good groups with the jacket bullets, and not your cast tells me there is something wrong with your cast boolits.
The load I use for both 350 gr. cast and jacket is 43 gr. IMR-4198. Going up to 44 gr. started to open the group up. The big difference between my cast boolits and yours, beside the weight difference of 50 grains is that I size my cast at .460. If I size smaller, the groups open up. Most 1895 Marlins I have seen prefer .460 dia. for better accuracy over .458 or .459.

I agree with this. Bullets need to be sized .460. Also, I am not familiar with your lube, but have heard that Rooster Red does not store for long periods of time.

You're problem could be ignition related, but I would lay money on bullet friction differences. The only way to modify bullet friction is with alloy, size, and lube. Reading your description, it appears your alloy is the same, but you say your sizes run from .458-.459. That's not a whole lot of difference in size, but it can cause you untold misery in accuracy.

[44man]

Change powder to see what happens. I had pressure and velocity excursions all over the map with 4198, acts like 4227.
Try 3031.
I also agree with .460".

[cajun shooter]

I would try several things to improve your results but only one at a time or you are back to square one.
On primers, I would try CCI Bench Rest
On crimping, I would try using the lyman taper crimp die
I would try an alloy that is 12-15 BHN
I would try making sure that the barrel is rested on the same spot each time as another member suggested. ( It's very important to have this or bbl harmonics will play havoc with results)
Have you checked the stock clearance for the length of the barrel?
Have you checked the torque of the screw at the attachment point?
I would try another bullet lube as this can change your poi
I know that some of my suggestions are very basic but that is how you find problems.
If using a light powder charge, make sure that you use a Dacron like material to fill your case. Position sensitive powder needs to be at the primer for results. Good Luck David

[jhunter77]

well I finally got cast to shoot good but it is a very low velocity load. 14grains of unique was the ticket. 13 grains of red dot was also not bad but was even a slower load. I am sure 1200fps kills just fine but I am looking for a little more umph for hogs. I normally shoot 3 shots fairly quickly with jackets and cast. Hog hunting I have snuck a group and been able to get 3 hogs on the ground a few times now so that is the reasoning in three shots from a cold barrel. That results in a sub 2" group almost always with jackets. I was able to do the same thing with unique today.

With that said, there are now two possible issues. I believe its the first, or a combo of both.

1) Undersized bullet for that barrel
2) Too light of a bullet for 4198 thus causing erratic burn, then when you step up to enough pressure for a good burn, you are too fast

I will slug it this weekend and see what it shows and then will order a mold and sizer. Any advice on a mold? I would like a very flat meplant and figure I will keep them around 300 grains if possible for the recoil and flat shooting. I am thinking 1700 to 1900 fps. This most likely will take a gas check correct?

[jhunter77]

sorry about the font.

[MtGun44]

Good old Unique. I usually recommend starting at 10 gr and working up to about 15 gr,
stop when you like the results. You fit the pattern. Glad to hear another good result
with a very unique powder. :bigsmyl2:

Bill

[jhunter77]

too bad its hard to find.

[jhunter77]

I slugged the barrel. .45765 My bullets measure.45870. Not sure if a .459 bullet wouldhelp. At this point it appears to be thewrong powder for the job. I am surprisedthat so many cast loads praise 4198. Mayhave to try another powder to see if I can get to the 1700 fps range. I do plan to try some larger bullets and see if I can get the velocity up some.

[Airman Basic]

Reloader 7 if you can find it.

[41 mag fan]

3031 behind that rcbs mold for my rifle

[Hickok]

Change powder to see what happens. I had pressure and velocity excursions all over the map with 4198, acts like 4227.
Try 3031.
I also agree with .460".I had the same experience with Imr 4198 and a 405 gr boolit in my Marlin 45/70. I had a hang fire, with this powder and decided not to use any more of it.

[Toymaker]

To be honest, I'd step up to a 405 grain bullet, .459 diameter, 30:1 (BHN 10) and Accurate 5744. Probably something around 23.5 grains. IMR 4759 would be my first choice, but it's being discontinued. Recoil is a non-issue.

[44man]

To be honest, I'd step up to a 405 grain bullet, .459 diameter, 30:1 (BHN 10) and Accurate 5744. Probably something around 23.5 grains. IMR 4759 would be my first choice, but it's being discontinued. Recoil is a non-issue.
I never got 5744 to work but Varget was an eye opener. 4759 is great and I just bought 16# of it to add to my stash. I will stay with 3031 in the rifle.

[Hickok]

I never got 5744 to work but Varget was an eye opener. 4759 is great and I just bought 16# of it to add to my stash. I will stay with 3031 in the rifle.44man you have picked a winner, as I believe that 3031 was Paul Mathews favorite powder listed in his book, "40 years with the 45-70."

[44man]

3031 is also proving to be the powder in the 30-30 with cast too. I had IMR 4895 working well but H4895 sent it to pot. Seems faster then IMR.
With about any caliber, I found 4198 did not live up to expectations. It seemed OK with jacketed in the 45-70 but not with cast because of reduced friction, seems the powder needs held back more.
Now 3031 does not all burn in my 10" 45-70 revolver but accuracy was still good. It is great in a rifle and actually has less recoil then 4198.

[Larry Gibson]

3031, 4895 and slower powders work well with 400+ gr cast bullets in the 45-70 at velocities over 1400 fps. However, the OP is asking about 300 gr cast bullets. Cast bullets of 350 gr or less just do not have the mass given the expansion ratio of the 45-70 to cause enough psi for those powders to ignite and burn efficiently at 1400 fps or less. Even the "slower" fast powders such as 2400, 4227, 4759, 4198 and 5744 will not burn efficiently under 300 gr or less cast bullets even with a Dacron filler. Unique has proven the best powder for cast bullets of 250 - 300 gr for velocities in the 1200 - 1500 fps range in the 45-70.

Larry Gibson

[pls1911]

Don't kid yourself.
At your normal snap shooting distances, that sweet Unique load will body-slam those porkers in the dirt!
The load is easy on you and the gun, but hell on pigs.

[W.R.Buchanan]

I have an RCBS 45-300FNGC mould that they made for me that drops at .461-2. The mould I complained about dropped at .458 with wheel weights. This is too small for a .458 bore. It seems that RCBS spec'd dimensions of all their moulds around the shrink rate of Linotype.

My new boolits drop at 325 gr and are slightly longer than my original mould, I size to.460. 25 gr of 5744 is my go to load for this gun (Marlin 1895 CB 26" bbl.)

One thing that had not been talked about on this thread is removing ALL the Copper from the barrel before shooting cast. I has been talked about extensively on this site.

I had never thought this mattered a whole lot however after fighting my Enfield #4 Mk1 for a couple of months. I finally got serious about cleaning the barrel.

I used 4 different bore cleaners, brushes and many patches before I finally got the bore clean. This took nearly 1 hour to accomplish! It made all the difference in the world! the gun went from being a 3-4" gun at 50 yards with my Cast Loads to a 1" gun. (iron sights)

If you are trying to shoot cast and jacketed interchangeably you probably are not going to see the best accuracy from your gun. You can shoot jacketed after cast with no big change, however it doesn't seem to work the other way.

Something else for you to consider in your quest for the one hole group.

Randy

[jhunter77]

Thank you. A kind member sent me some 460 sized ammo to try. I will report back with the results

[dlbarr]

+1 on Unique with the 45-300-FN.

That bullet with 16gr Unique shoots great out of both my HR & 1895.

[44man]

+1 on Unique with the 45-300-FN.

That bullet with 16gr Unique shoots great out of both my HR & 1895.
Not me, case is too large for a shotgun powder. Can't even make it work in my revolver. 4759 in the revolver and 3031 in the rifle.135843 All the boolits I shoot from the revolver 45-70, notice i had 3/16" groups at 50 yards. 10 shots at about 1".

[stubert]

49 grains 3031, Win. cases rcbs 45-300gcfp youll like that.

[grouch]

I agree with the previous poster who suggested a softer alloy. My Rolling Block shows a decided preference for 18:1 lead and tin over the wheel weights + 2% tin - maybe bumping up?
Grouch

[44man]

Rolling block with 1 to 20 and 3031 was amazing. I love soft lead when it works.

[jhunter77]

well The Ranch dog mold was the ticket sized at .460 I tried a friends RCBS and casted a few and sized them 460 but the mold only threw them out a 459 . I belive it has to do more with the size. Using straight WW's it takes something like unique to bump them up quickly. 4198 is just too slow. The RD mold is about 25 grains heavier and also is properly sized for the bore. I hope to drop to 50 50 clip on to sticky ww's but will have to wait and see if I can find a mold for sale.

[44man]

I refuse to believe in "bump up". Fit will be where it is at.
I have never had unique work in a large case.
I want to know who says the gas pressure is even at the base when powder is laying on the bottom of a huge case? Can the boolit be "cocked off center"? I am too stupid to understand this. Every gas molecule must fly to the center of the boolit.

[Doc Highwall]

I have used IMR-3031, 48-53 grains with a 385 grain cast bullet in my 1895 and have gotten great results. A 400 grain lead bullet with 24-25 grains of 2400 powder is very close to a 70 grain charge of black powder and does not require a filler. A member here just recently posted about his wife shooting a 225 lb bore with a 1895 Marlin with a load something like this.