Lee 405 hollow base lube question

[218bee]

Decided to try the Lee mold in my Trapdoor as I've heard nothing but good about it. I only shoot with Black in this gun and have been using various solid base bullets with Bullshops NASA lube and 60-65grs of black with a .030 wad between bullet and powder with some compression. Wondering if with this hollow base design any of you put lube in the base or not. Probably not needed, maybe defeats purpose? Or just use lube grooves? Or try both and see? What say ye?

[13Echo]

Lube the grooves and leave the base empty. Been working good that way since 1873.

Jerry Liles

[jonk]

Also, no disc needed- might pack into the HB unevenly and throw things off.

[218bee]

No wad eh??

[Larry Gibson]

218bee

No wad at all. That was tried with the 45-55 carbine load and abandoned after the wad caused accuracy problems. BTW; the HB is not there in the M1873 bullet to cause the base to flare into the rifling ala minie style. It is there simply to regulate the weight of the bullet whi,e maintaining the same overall out sider dimentions. Note how thick the skirts of the Lee (It pretty much replicates the original M1873 bullet) 405 HP bullet are? They are way too thick to obturate.

I suggest no lube in the base, no wad and to shoot the bullets cast of 20/1 lead/tin "as cast" either with BP or smokeless powders.

Larry Gibson

[218bee]

Well, I am going to try as cast, nasa lube, black (of course), no wad, and we'll see how she goes. Thanks for the info. Hopefully be shooting on Fathers Day.

[montana_charlie]

Note how thick the skirts of the Lee (It pretty much replicates the original M1873 bullet) 405 HP bullet are? They are way too thick to obturate.
If a solid bullet will obturate, why would not a hollow based one obturate even more readily?
CM

[Larry Gibson]

If a solid bullet will obturate, why would not a hollow based one obturate even more readily?
CM

Not saying it won't obturate but it doesn't as much as you might think. There just isn't enough pressure to expand the heavy skirts of the original M8173 bullet. 218bee is using them in a trapdoor. What Frankford Arsenal found was the .459 size M1873 bullets were not obturating with the rifle load let alone the carbine load. In 1879 a "bore scraper" was issued with the cleaning kits to removed BP fouling and leading. This also led to the adoption of the heavier massed 500 gr bullet which would obturate into the .460 to .465" groove depth of the trapdoors rifling. The 405 gr bullets just did not have the mass (weight) to offer enough resistance for complete obtruation necessary at the accelleration rate of the BP load. This is all well documented in the more complete historical works on the M1873 Trapdoor rifles. Granted heavier and faster loads in the 45-70 will cause the 405 bullet to obturate but those loads are beyond the safe capability of the M1873 Trapdoor.

Larry Gibson

[405]

Since you're shooting blackpowder why not experiment and find out with your loads and equipment. I can think of several cominations to try. Maybe load five of each combination. Use a good rest and good techniques under good conditions. Shoot five. Clean. Shoot five. Clean. Shoot five. Clean... etc. Check the targets. The answer may be on the targets.

[218bee]

I'll definately experiment.....thats what I do...just looking for tips on where to start

[405]

It would take REALLY A LOT of trials given the number of variables but no hurt in taking a stab at trying maybe 4 or so. Using one type of wad and one type of lube and the same amount of powder give or take a few grains because of changing capacity with the lube and wad variables. I'd try to keep the OAL the same and the amount of compression the same.

Say....
5 with only bullet on top of powder.
5 with only wad and bullet.
5 with only lube in cavity.
5 with wad on powder and lube in cavity.

Other variables could include: bullet alloy, bullet diameter, OAL, type and thickness of wad, type of lube, amount of compression, grade of powder, neck tension.... and others- the permutations would be staggering.

Seems like, with the 4 trials though, you might be able to see enough trends in accuracy to say, "better or poorer"?

[13Echo]

I think the best place to start is duplicating the government loads. My friend, Bo, has excellent results with a carbine load of 59grs ffg compressed enough to allow seating the 405gr Lee to get a firm crimp over the front band. The bullet is cast of 30:1 alloy at 0.460" and is lubed with a homemade BP lube and primed with a Federal 215m. The crimp seems to be important and needs to be firm. We've also tried the same bullet over 70grs of very heavily compressed powder with good results. My rifle seems to prefer the SAECO version of the 1881 500gr bullet over 70 grs ffg.

Jerry LIles

[45 2.1]

Not saying it won't obturate but it doesn't as much as you might think. There just isn't enough pressure to expand the heavy skirts of the original M8173 bullet. 218bee is using them in a trapdoor. What Frankford Arsenal found was the .459 size M1873 bullets were not obturating with the rifle load let alone the carbine load. In 1879 a "bore scraper" was issued with the cleaning kits to removed BP fouling and leading. This also led to the adoption of the heavier massed 500 gr bullet which would obturate into the .460 to .465" groove depth of the trapdoors rifling. The 405 gr bullets just did not have the mass (weight) to offer enough resistance for complete obtruation necessary at the accelleration rate of the BP load. This is all well documented in the more complete historical works on the M1873 Trapdoor rifles. Granted heavier and faster loads in the 45-70 will cause the 405 bullet to obturate but those loads are beyond the safe capability of the M1873 Trapdoor.

Larry Gibson

Probably so with a 20:1 alloy, but you go down to between a 40:1 to a 50:1 alloy, then they will obturate and shoot better groups.

[Larry Gibson]

45 2.1 is correct, you can go to a softer alloy and get obturation. However, Frankford arsenal did a considerable amount of testing and found the 20/1 alloy to give the best accuracy with the M1873 service load. They also found it to be the best alloy for the carbine load. They also found that the softer alloys when used in the 1300+ fps range of the service loads leaded badly and accuracy was up to that of the 20/1 alloy. With the adoption of the 500 gr bullet the mass of the bullet was such that obturation was complete with the standard 70 gr of BP of the service load. We must remember that all of this was early in the development of cartridges. It was believed back then that obturation (or as we call it here sometimes; "bumping up") was the correct way. Subsequently, it was found that much better accuracy was possible if the bullet correctly fitted the groove depth. This is why many still recommend "slugging the bore". In the last few years it has become known that the best accuracy with cast bullets is when they correctly fit the throat. Unless someone has a really esoteric groove depth very few use "bumping up" or depend on obturation for accuracy. A bullet that properly fits the groove depth or the throat will always provide better accuracy.

In the case of the M1873 Trapdoor the original ammunition depended on obturation. It was found the 405 gr bullet did not sufficiently obturate and a 500 gr bullet was adopted that would. These days it is much easier to simply use a bullet that fits the throat or groove depth. The Lee 405HB most often has an "as cast" diameter that that is closer to groove depth or fits the throat and requires no obturation whether cast hard or soft to seal the bore. Thus when shooting "as cast" Lee 405HB cast bullets accuracy most often is better than if sizing them down to .459. Some years back I discussed this with Spence Wolf. He concured and said he too most often got better accuracy with unsized Lee 405HB bullets. However he was reinventing the wheel in his book (replicating service M1873 loads) and he , in fact, succeeded. If one follows Spence's instructions in his book very good M1873 loads can be replicated both in performance and accuracy.

But the point here is that not depending on obturation will result in better accuracy. This is especially the case with the Lee 405HB bullet if you want loads in the 1250-1350 fps range. The 20/1 or 16/1 alloy (adopted as the best for the 500 gr bullet at 1315 fps) is necessary for best accuracy. Just ask; "how many BPCR competitors don't use 20/1 alloy?" and you have the reason.

Larry Gibson

[montana_charlie]

When reading a long piece that I want to fully understand, I read slowly...and re-read some sentences as I go to make sure I am keeping everything in context. At the same time I keep (sort of) a mental notepad off to the side where I highlight any 'pearls' that seem to appear.

I fully agree with the final point which said, "But the point here is that not depending on obturation will result in better accuracy."

After finishing...maybe finishing several times...I go back to examine the pearls.

Boiling down the long post just above, I have been given to understand that...
In order for a bullet as hard as 20:1 to obturate, it must weigh at least 500 grains and be propelled by at least 70 grains of black powder.

Lighter bullets don't have sufficient mass, and smaller charges don't have sufficient energy.

Therefore, any somewhat undersized 405 grain bullet would probably need to be fired in a 45/90 to get obturated...and the 'express' bullets typical in lever action loads never did.

It could make one come to believe that no 38/55 load could ever obturate properly...

Does anyone else see this 'pearl' as having a flaw in it's surface?

CM

[45 2.1]

When reading a long piece that I want to fully understand, I read slowly...and re-read some sentences as I go to make sure I am keeping everything in context. At the same time I keep (sort of) a mental notepad off to the side where I highlight any 'pearls' that seem to appear.

I fully agree with the final point which said, "But the point here is that not depending on obturation will result in better accuracy."
Generally, but depends on fit and the load, regardless of powder type.

After finishing...maybe finishing several times...I go back to examine the pearls.

Boiling down the long post just above, I have been given to understand that...
In order for a bullet as hard as 20:1 to obturate, it must weigh at least 500 grains and be propelled by at least 70 grains of black powder. At least in Larry's world. Lots of ways to cheat this though.

Lighter bullets don't have sufficient mass, and smaller charges don't have sufficient energy. That depends on what size the combustion chamber is, load type and whether the boolit is retarded or not.

Therefore, any somewhat undersized An assumption! 405 grain bullet would probably need to be fired in a 45/90 to get obturated...and the 'express' bullets typical in lever action loads never are you sure about that? did.

It could make one come to believe that no 38/55 load could ever obturate properly... They can and do, nicely...........

[montana_charlie]

[b]That depends on what size the combustion chamber is, load type and whether the boolit is retarded or not.

An assumption!

are you sure about that?

They can and do, nicely...........
No need to toss sand in my oatmeal, Pal.
I was just ticking off the things I would gather from the post I was commenting on.

If you see a flaw in that pearl's surface, take it up with the author.
CM

[45 2.1]

No need to toss sand in my oatmeal, Pal. Well, it's good that you did find some of the deep cracks in that tome. Writing diferences do make things difficult at times.

I was just ticking off the things I would gather from the post I was commenting on.

If you see a flaw in that pearl's surface, take it up with the author.
You post was posed as a question, which you got an answer to. You didn't say take it up with him, which is a useless endeavor anyway since he writes long winded posts and doesn't answer questions (but that is old news anyway).

[Limey]

218bee,

....I only use the Lee 405grain hollow base mould in for both my Marlin 1895 and my Pedersoli Sharps replica....

...with both BP and smokeless....

.....I cast my bullets from wheel weights and water quench them...

...bullets are sized to .459 in a Lyman 4500 using home made lube based around bee's wax plus other ''slippery stuff''...

...I always get lube in the hollow base, never remove it and in both guns they shoot really well, more accurate than I deserve, put meat on the table and very neat, round, tightly grouped holes in paper.....

....so I don't worry about it anymore....try it, it may work well for you as well.

Safe shooting,

Limey