Trying to find accuracy in a 45-70 405 Gr Bullet with 4198 powder.

[Les in Wyoming]

Question: Is this one of the old Microgroove barrels? My family had one of those in 30-30 and it shot jacketed bullets just fine but couldn't hit the broad side of a barn with hard cast lead. It seemed like the rifling was just not grabbing the bullet and it acted like a smooth bore.

I think this is called a Ballard groove. It is in an 1895 Cowboy.

 

[Les in Wyoming]

Lee 405 gr 45-70 cast bullet

www.shootersforum.com

It's an old thread but there's some good advice in there, other than the people saying to try a different powder, etc. OP on that thread had same issue as you.

For a TLDR of that thread; A couple people said lightening the crimp a bit can help, as well as aiming for 1200 FPS, as that's the sweet spot for the 405's apparently. There's a decent amount of information there

Thanks much for this

 

[imyourhuckleberry]

Question: Is this one of the old Microgroove barrels? My family had one of those in 30-30 and it shot jacketed bullets just fine but couldn't hit the broad side of a barn with hard cast lead. It seemed like the rifling was just not grabbing the bullet and it acted like a smooth bore.

The Lyman Cast Bullet Handbook states that if it does have microgrooves since they are shallow BHN should be at least 15 and velocities should be kept under 1600 fps for acceptable accuracy.

 

[RT2506]

The latest model of the Marlin 1895 rifles have Ballard rifling which is basically standard style rifling. They shoot cast OK.

As you have found out it is the bullet that was the problem. What is the actual measured diameter of those bullets? Also what is the actual measured diameter of your coated bullets that shoot good? If I was a betting man I bet the first bullets are actually too small probably .456/7 and your coated bullets are .458 or larger. That coating adds diameter especially if they were not run through a sizer after they were coated.

If you have a bunch of those first bullets go to Harbor freight or order on line some of the powder coating and coat them your self. YouTube is full of how to do this videos.

 

[Mrkdiver]

I appreciate the input. I will try the primers. With this 4198 powder, I just went out and shot 35 grains, 36 grains, 39 grains and 41 grains (having already tested 37,38 and 40 grains). I am shooting open sights at 60 yards. Some of these were impossibly inaccurate. I had 2 - 16" targets side by side and only 1 out of 3 hit the paper! On others, they might hit 2 on paper 14" apart and the other missing. I did get a 3" vertically slanted group with 35 grains. This is beyond crazy. The gun does shoot a fair 2" group with the 300 grain Sieras and 40 grains of the 4198.

I am seating them at the spec in the Lyman book - 2.550". Lyman has max load at 40.5 grains. I have seen others use more under a 405 grain bullet. (This is a Marlin 1895 CB). I am thinking of trying a bit hotter. I just don't know which way to go. I am limited to 405 grain bullets and 4198 powder.

I also just cleaned the rifle thoroughly also. If there are any other suggestions or shots in the dark, please let me know. I just don't see how these bullets can shoot so wild at 60 yards off a rest.

I shoot cast 405's all the time and have been for years, try slowing them down with less pressure. When this has happened to me it has always been to soft of a cast bullet, not all batches turn out the same. Don't know anything about powder charges with 4198

 

[lotech]

I no longer have a Marlin .45-70 but had a Micro-Groove version for years. Regardless of the rifling type, best accuracy will likely be obtained using the largest diameter bullet that will chamber without difficulty. This will probably be .459", maybe .460". .457" is probably too small for decent accuracy regardless of the type of rifling. I had good luck with the RCBS 405 flat nose gas check and the Lyman #457193 flat nose plain base, both around 410-420 grains in wheelweight alloy. IMR4198 provided good accuracy, but I used a max. of 33 grs. The Marlin was hard kicker beyond that for me.

 

[robert6715]

Cast boolits are a totally different animal. The cast boolits have to be sized to fit your bore. You start by slugging your bore with soft lead to figure out the groove diameter. Then you size your cast boolits .001 to .002 over your slugged bore diameter. Shooting undersized cast boolits results in inaccurate loads & substantial leading.

If you are going to shoot cast boolits that you did not cast & size properly yourself, you need to be ordering boolits sized appropriately for your bore. Many of the guys that specialize in selling cast boolits offer them sized to fit your bore, i.e. .458, .459, .460

Boolits = cast
Bullets = jacketed

 

[Flintlock]

I have a Sharps with 36" barrel and I shoot the 405 grn bullet, sized .458. I use 30 grains of IMR4891. Not sure of the velocity but it shoots under 2" at 100 yards with rear tang peep site. It has taken deer with this bullets.
I also likes the 405 Jacketed soft point and I push them a little faster with 35 grn of IMR 4891.
Glad you found a bullet it will shoot.
Mike

 

[CHAGA50]

Okay I may cause a little mischief with this post , BUT here goes !
I have notice all my handloads have the same accuracy at a uniform speed ( ie )
anything traveling between 1300 to 2000 fps, is very stable whether I shoot cast or jacketed slugs .
my best groups are at speeds around 1800 to 2200 fps , and yes the recoil is there but so is the accuracy , my 100 yard groups fit under a milk jug cap , also I must mention this ! The 45/70 case was designed to be full of black powder the bullet needs to sit firmly on something , when you use to small of a powder charge this creates a cavity in the case which I believe affects accuracy . I use ground cornmeal to make up the difference in the case to keep the powder tight to the primer , just remember to leave enough room in the case for the bullet to reach the crimp ! Do not use the box kind it's full of salt and other things , Just head over to the nearest hippie store for the organic cornmeal only ! I went to the range and shot this load , the guy next to me kept looking around the range , He just knew the grass was on fire LOL !
I finally told the guy what I was doing but only after I could not keep from laughing , The poor guy was so busy looking for a fire he wasnt shooting anymore

 

[Alibiiv]

I am shooting a Marlin 1895 CB and have procured a bunch of cast 405 gr bullets. I am limited to 4198 powder as I have invested myself in 8 + lbs of it.

This gun shoots 300 grain bullets accurately with 40 grains of IMR 4198. I have the Lyman book, but it is limited in loads. I have shot 37, 38 and 40 grains under a 405 cast bullet. They shoot all over the place like they were shot from a sling. 40 grains gives a hard wallop with the 405 grain bullet. I don't know that I want to go higher. I will if it would increase accuracy, however.

Is seating depth as critical in this round with a heavy crimp? Should I chase the lands of the rifling and ignore the cantilure? Or should I just load it to the recommended OAL? I could really use some helpful input. Thanks

I am quite certain that it is not the powder and it is not the primers that is causing the inaccuracy. There are a lot of variables here that one has to take into consideration when loading cast bullets and I did not see any of them addressed in your original post. First and foremost what are you using for lead, what is the Brinell hardness of the rounds that you are shooting? The best hardness ought to be up to 22.0, and I suggest a gas checked bullet to get a good seal. Next what is the diameter of the bullets that you are shooting and how did you size those bullets? What is the mold number for those same bullets, and what are you using for a lube? Have you tried purchasing some factory cast bullets to make a comparison. Rim Rock bullets makes a hard-cast bullet with a gas check that I have been considering to try in my Marlin 1895, 45-70; I've used their bullets in other guns. Also have you tried some factory, jacketed bullets in your rifle to see what you are getting for groups with the factory stuff. I reload for two Marlin 1895s, both will shoot one-inch (usually two shots in one hole), three shot groups at 50 yards consistently with just about any jacketed bullet that I put through them, and.....4198 (48 grains) is the go-to powder. As for chasing lands with the 45-70, I would say that yes you can try chasing lands, but I don't think it is possible to do with the round. This rifle does have a significant recoil and your bullets "will" back out without a good, solid crimp. You cannot ignore the cannular groove, if you do you will have a problem. The overall length for the 45-70 "is" determined by the cannular groove, so the overall length will be determined by the bullet and not the SAAMI specs in your reloading manual. Case in point is if you are loading the Leverrevolution bullets, the casings have to be trimmed back to suit the bullet; so your casings are shorter if reloading Leverrevolution bullets. I strongly suggest that you try the going the jacketed bullet route first just to see what the rifle will do. Lastly or maybe ought to have been firstly, is check the sights on your rifle to make sure that everything is tight and not moving around, especially the front sight, sometimes the dovetail can be just a little loose and that will throw everything off tremendously. If all else fails, "maybe" an eye test and some glasses??! These guns in this caliber shoot, I am sure you can get the accuracy that you are looking for, gotta get the right combination.

 

[Traveling Tech]

I am shooting a Marlin 1895 CB and have procured a bunch of cast 405 gr bullets. I am limited to 4198 powder as I have invested myself in 8 + lbs of it.

This gun shoots 300 grain bullets accurately with 40 grains of IMR 4198. I have the Lyman book, but it is limited in loads. I have shot 37, 38 and 40 grains under a 405 cast bullet. They shoot all over the place like they were shot from a sling. 40 grains gives a hard wallop with the 405 grain bullet. I don't know that I want to go higher. I will if it would increase accuracy, however.

Is seating depth as critical in this round with a heavy crimp? Should I chase the lands of the rifling and ignore the cantilure? Or should I just load it to the recommended OAL? I could really use some helpful input. Thanks

I cast my own bullets for 45-70. My rifles are both 1885 hi-walls. Not all cast bullets are created equal. The powder is almost certainly not the problem. I shoot 535g "money" bullets from my buffalo arms mold, sized at .459". My powder is imr 3031 at 37g. Lots of guys I shoot buffalo silhouette with shoot 5744 I believe. Lead should usually be sized .001 over bore. Are your bullets lubed? Lead bullets must be lubed. You want to stay under 1800fps unless you use gas checked bullets. Too fast, or no/poor lube will cause leading and once it starts it gets bad quickly. Leading of the barrel will do what you are experiencing. Poor casting practices will cause air pockets inside the bullets and be harmful to accuracy as well. I hope this helps.

 

[Traveling Tech]

Okay I may cause a little mischief with this post , BUT here goes !
I have notice all my handloads have the same accuracy at a uniform speed ( ie )
anything traveling between 1300 to 2000 fps, is very stable whether I shoot cast or jacketed slugs .
my best groups are at speeds around 1800 to 2200 fps , and yes the recoil is there but so is the accuracy , my 100 yard groups fit under a milk jug cap , also I must mention this ! The 45/70 case was designed to be full of black powder the bullet needs to sit firmly on something , when you use to small of a powder charge this creates a cavity in the case which I believe affects accuracy . I use ground cornmeal to make up the difference in the case to keep the powder tight to the primer , just remember to leave enough room in the case for the bullet to reach the crimp ! Do not use the box kind it's full of salt and other things , Just head over to the nearest hippie store for the organic cornmeal only ! I went to the range and shot this load , the guy next to me kept looking around the range , He just knew the grass was on fire LOL !
I finally told the guy what I was doing but only after I could not keep from laughing , The poor guy was so busy looking for a fire he wasnt shooting anymore

Many use veggie wads or as I do, use toilet paper. I cut each square into fourths and use an ink pen with a flat end to stuff it in the case like a shotgun wad. My accuracy was noticeably better. I use the cheap stiff tp.

 

[jfloyd]

OK, latest update (head scratching). I loaded up several charges and shot them at 60 yards. I tried 34 grains IMR 4198 (going down) it shot horrible. Maybe a 10" group. Then I tried hotter loads going half-grain from 41.5 up to 43. The 3-shot groups were so incredibly sprayed, you would think it impossible. I could be more accurate with a sling shot. Some were 18" groups. (BTW, I gave the rifle a good thorough cleaning prior to this). These are cast 405 grain bullets I bought at the store.

So, I also had some other bullets I was able to buy recently. They are also 405 grain. Same shape. They are polymer coated measuring .457. I dumped 40 grains of 4198 under them. The results are in the attached pic. I am greatly relieved it isn't the rifle. I need to bring the sight over a bit, but at least they are together. Two in one hole and one next to it. So you guys were right that it is the bullets. Had these polymer bullets not shot well, I would have considered this rifle to be a wall hanger. But those bullets were the same shape and same weight. So how do you know you are getting good bullets when you find some?

We are going to try to shoot those other bullets in my son's gun to see if they shoot better in his. Assuming they don't (likely) is there anything I can do to make them shoot better? They do not have a place for a gas check on the back. Obviously, it is not the powder charge.

The only way to salvage those bullets assuming they are undersized would be to coat them IMHO. There a few options out there to coat your own but if they are already lubed that may be out of the question too. Last resort is to recast them to proper size.

 

[tacosupreme]

I got some HSM brand .459" 405 grain cast bullets from Murdoch's in Riverton a while back. I put them over 13 grains of trailboss in my 1886 Winchester (made in 1887) and they are more accurate than I am, but they don't feed well seated to the crimp groove, so I seat them a little deeper. I use the Lee factory crimp die and really like the results. I know that doesn't help your situation, but bullet diameter with cast is pretty crucial. My barrel slugs at .458". Many molds cast at .460 or more, and then go through a resizing die for the particular barrel they are being fed through. As a minor footnote, the same load shoots 1" groups at 100 yards with my BFR revolver as well.