New Lyman #457125

Here is a new Lyman #457125 500gr mold for .45-70. During initial inspeciton I noticed there was something funny about the alignment. Thought it was caused by a burr right next to one of the alignment pins that might guide the halves off-center. I removed the burr and adjusted pins out a bit to cut all the play but still, to me, the way how the halves come together looks worse than that of my .358" Lyman molds. Is this considered normal? Thanks for any advice.

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Send it back! That's what I would do anyway. New moulds should cast round boolits and the halfs should line up!

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Agree with hunter74. That's not right. Send it back.

Thanks guys for replies. After reading Lyman warranty policy I noticed it wouldn't apply in my case. I got this from a friend in U.S. who ordered it from Midway. As I'm not the buyer, I should have sent the mold back to him first and pay all charges. Not really worth it.

Thought to give this mold a go anyway so here are first results. While eccentricity of end products can be seen if looked really close I think these might still hit angle of a moose. Had to run the pot about 800F to get good fill out of bases but once casting temp was reached it was really easy to get good fill out. I don't know composition of this alloy. It's a mix of all kinds of lead with some tin added, just in case. BHN is about 10, says my noob thumb nail. Boolits weigh 510 grains.

I guess the biggest problem is that the boolits drop out only at .457". When all else casting parameters were kept the same but mold was switched to two cavity Lyman #358430, a .38 cal. 195gr RN, these bullets came out at .360" which is pretty much as they should.

https://img.aijaa.com/b/00224/14644636.jpg

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If they drop too small, use more sb

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CeeHoo,

No, your mold halves do not meet correctly.

Definitely try a little more antimony.

After that you could try to "Beagle" it or lap it out. "Beagle": Aluminum tape across one or both faces of the mold to enlarge the castings.

https://www.youtube.com/watch?v=kIfcbDCYQPw

Or, buy a mold that will cast the correct size to start with. (New Lymans are notorious for casting undersize.)

http://noebulletmolds.com/NV/index.p...ugtmk5vbi3tc13


Onnea!

Lapping is an option, especially since it is casting rather small (typical for a modern Lyman). Some more tin and pressure casting with a ladle might give you another .001"... maybe.

If you decide you have nothing to lose, you could always try physical persuasion. Put one mold block in a vise and whack the other one with a hammer. Check carefully between each hammer hit until it lines up. What you'll probably find is you can line it up, but if will freely shift back as well. Then you'll need to peen the slack side of the alignment hole with a hammer and punch. Again, one hit at a time and check the results carefully before continuing. Peen it only enough to take up the slack, but will still close fully.

If you peen the hole edge too much, just file it back with a round needle file.

It's crude, you may ruin the mold, but you may save it. After much use you may find it needs another "tune up" in the same manner.

Lapping it will help with both issues you have. Size and cavity alighnment. O have the pot hot when lapping a mould . Make a few lapps from bullets (3 or so is more than enough) Start with 240-280 grit compound and work the cavity for a few revolutions clean mould and warm up on pot. cast a few bullet to get new size. 320 grit and a few revolutions then clean and cast a few checking size. 400 to 600 grit here and run to desired size.

To Lap a mould out isn't hard just time consuming.
Make your lapps I drill the base for a piece of 1/8" key stock and glue it in with epoxy leaving a 1 - 1 1/2" stem
Use a T tap handle to hold the lapps
Impregnate the lapp with desired grit by smearing a small amount on flat steel plate and rolling lapp between 2 plates. this pushes the lap compound into the surface of the bullet.
Lightly oil the cavity and insert the lap into the cavity. I like to hold the blocks in a small toolmakers vise.
With a tapping motion Back and forth rotation 1/4-3/8 turn make 3-4 rotations rotate 90* and repeat thru 2-3 complete rotations.
You should see the cutting pattern now when you clean the blocks. Clean and warm cast a few good bullets
With a new lap and next finer grit repeat above till your at size you desire. I would lapp this out to around .460 as cast with a known alloy
A side note The 457125 is nose riding check size of nose to rifles bore If small you can lap it up at this time, if not be careful applying compound so to not get any on nose.

Done right and evenly this will make a very round bullet to desired size

Before lapping remove any and all burrs fit pins to closest possible, and make sure everything is right. Your hand fitting this mould to these settings a burr wears quick and will change alihjnment when it wears away. A dowel with a pointed end and some of the compound will polish the holes edges with a few spins removing burrs and or dings. Also look around pins for burrs dings and raised edges. Here if they are there remove pins deburr chamfer with the dowel and replace pins.

Lapping isn't a speed event work slow and careful pay attention and you end up with a very nice mould that casts very accurate bullets.

When lapping a mould remember removing .001 is .002 on the dia since the .001 is removed all around.

Many pieces of advice here, thanks a lot.

At the moment and with intended purpose in mind, it may be I don't have to do anything, other than casting & loading some more. A couple of days ago I made a test round and fired it. As it hit my target, left a round hole and didn't leave observable leading into the bore I decided to load seven rounds more to check accuracy potential on limited basis. Boolits were tumble lubed and used as cast. My load was a Trapdoor max load from Lyman's fourth edition which is 43.5 grains of N135. A really mild shooting cartridge.

The rifle I used is my Finnish m/39 .45-70 conversion with 27" barrel and open sights. I don't know its exact groove diameter but it has fairly steep 1/16" twist. First I shot and chronographed three rounds and went to see the target after every round. Distance was 50 meters. As those three shots made reasonable sized group of 2.3" (marked in red) and I still didn't see leading in the bore I was comfortable enough to fire the remaining four rounds in a row. Those made a group of 1.6" which in my opinion is well adequate for moose. Still no leading in the bore. I guess obturation was there.

It was also nice to notice that this load has tendency to shoot to right. All the lighter flat noses I've tried, be it semi-jacketed or commercial hardcasts, have shot to left for which reason the front sight blade is adjusted quite a bit to left also. With this load it could be adjusted quite close to the barrel axis.

Average velocity measured at four meters from muzzle and at 32F temperature was 1381 ft/s which is kinda slow but don't they say that .45-70 performs best when punkin is rolled slow and heavy?

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All my BPCR loads with the heavy end bullets 510 lyman round nose 535 postell and a 550 grn by old west moulds run in the 1150-1200 fps range ( muzzle velocity) shoot very accurately hand have no trouble with rams at 500 yds.
Your load with the lyman bullet at 1380 should be a fine load. More velocity is going to raise the recoil also

Nice twist on the story . Well done Sr.

Nothing wrong with that velocity, should work well. Also, have to compliment you on the excellent photos.
If the mold were mine, I'd still give "beagling" a try. It takes little effort to do, and is completely and easily removed if it doesn't make any improvements.

Your mold definitely shows clear signs of misalignment, but your shooting seems to be quite good. Aggravating that the mold was sent from the factory with a defect, however the end result still is grouping. A 500 + grain lead bullet at over 1300 fps is no slouch! Keep shooting & tinkering. Might want to even try paper patching. As some of us over here say, "There are lots of ways to skin a cat." You just keep getting it done :) and best of luck.

how do you identify the 457125 with the .448 nose,? as the bigger nose will not shoot or chamber in a dirty bore,,wade

Hold the handles on the mold and twist them. If the mold halves are not lining up immediately… tighten the bolt on the handles

I would have never believed that wonky boolit would shoot ... but looking at your targets ...
... Well , that proves your rifle must like it ! Just goes to show ...you just never know untill you test the loads out .
If it groups ... keep it !
Edge that front sight over a tad and ... Keep On Keeping On !

I like your conversion ... it's neat !
Gary

Thank you fellows. In case you are interested in making similar Mosin-Nagant conversion from spare m/39 parts here are a few lines I wrote about my trials and tribulations. After second barrel with slower twist, the rifle became pretty good.

https://www.gunboards.com/threads/le...rnment.392777/

https://img.aijaa.com/b/00633/15124759.jpg

Well, this 457125 follow-up range report comes late but hopefully it's better than no report at all. Last weekend and two weeks before that I was at our 300 meter rifle range testing the remaining boolits I had cast with this mold back in 2018. Most of the boolits (.4570-.4575" in diameter) were tumble lubed in Lee Liquid Alox and loaded as cast. Some were sized to .457" with Lyman #45 lubesizer and Lyman Alox 50/50 grease. Once again I used the Trapdoor max load from Lyman's fourth edition of the Cast Bullets Handbook which is 43.5 grains of Vihtavuori N135. Cases were made by Starline and primers were Federal 210 for the as cast loads and GM210M for the sized loads. The choice of match primers for the sized load was simply because I ran out of 210s.

During the first visit at Jan 7th temperature was -10 degrees of Celsius (14F) with virtually no wind. Sky was cloudy and proximity of polar night didn't yield best lighting conditions for open sight shooting at 10 AM (sunrise at 9.50) but snowy backstop helped quite a bit.

I started the 300 meter shooting at rest with tumble lubed as cast loads. After three conditioning shots I fired the first five round group which, in my opinion, made a quite nice group of 17.5cm or 6.89". Second five round grop was worse, 26cm or 10.2", even though slowly improving lighting conditions made me see the black dot somewhat better. The third group went terribly for no obvious reason. Dispersion of 30.5cm or 12.0" made me call it a day and I decided to move to pistol range for testing some 105gr Lee SWCs with GP100.

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At home I cleaned the bore with oiled and dry patches noticing that there was virtually no leading in the bore or throat making more vigorous cleaning procedures unnecessary at that time.

Two weeks later in Jan 21th, during our club's next shooting session I decided to renew the test firing with similar setup. Temperature was -2 degrees of Celsius (28F) and almost no wind. This time sky was also clearer and lighting was somewhat better to begin with. Shooting began at 10 AM and sunrise was 9.25. Again I started with tumble lubed loads as I still had a few rounds left. After conditioning shots, the first five rounds printed a nice group of 15cm or 6".

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When shooting the next group I noticed after three shots that I had ran out of TL rounds and had to shoot two more rounds with sized load. The TL load had the point of impact as previously seen but the lubesized boolits were hitting about 8" higher and right. Those two shots were only about 1" apart.

The following group with lubesized boolits really made the day although I have to admit it must have been more matter of luck than plain excellence. I had a shooting buddy spotting each shot over my shoulder and to our delight those rounds made a really tight group of 10cm or 4". I'm sure more groups would have dropped me back to this Earth but as I had only two more rounds left this one became my "go home group" for the rifle.

The target was a standard ISSF 300 meter rifle target with 60cm black dot, 100cm one-ring, 5cm bullseye and 10cm ten-ring.

http://img.aijaa.com/b/00281/15124755.jpg

A couple of years ago I bought another new Lyman 457125. Back then it passed my visual inspection but I didn't try it for casting until yesterday. Looks like this mold may have been cut with a new cherry as it produces .460-462" boolits from range scrap. I could live with that but noses measure .450-.452". A dummy chambers and extracts but nose gets marked by rifling. Possibly a usable match bullet but perhaps too snug for hunting application.

I also got a Saeco #881 which makes .459" boolits from the same alloy. Possibly a better boolit but I seem to prefer Lyman's nose profile over the Saeco which, to me, has sort of weird "truncated cone" look to it even though it is essentially a round nose. Lyman is more round and appears to be similar to Ideals made in the late 1800s.