My design 45-70-430..Tumble Lube or Conventional Lube Groove???

[Walstr]

Although new to this addiction, I feel ready to embark on moulding a boolit I can't find elsewhere. My main crux is deciding Tumble or Conventional Lube groove? I've played with the wonderful "Mountain Molds Online Bullet Design" as follows, which approximates a tumble lube design:

Alloy = WW+2%Tin
Bullet Design = Bore riding Tangential Ogive

As-cast Bullet Diameter = .461" +0.002"
Crimp Groove = .055"
Front Band Diameter = .461" +0.002"
Bore Ride Diameter = .458" nominal
Front Band Length = .050"
Bore Ride Length = .060"
Nose Length = .500
Meplat = 70% (as a % of bullet diameter)
Base = Plain
G to B = .70 (groove-to-band length ratio)
groove angle = 45 deg.

Block = Aluminum
Sprue Hinge = stud & lock nut

# of Body Bands = 4
# of Lube Grooves = 3

Band Lengths = .083"
(inches) OAL = 1.046"
(inches) Groove c.to c. = .141"
(inches) Lube Weight = .793gr
(gr.) Naked Bullet = 429.7gr
Weight (gr.) = 429.7 + .793 = 430.93gr

Please, if anyone knows or already uses this boolit design, I would very much like to hear from you for your valued experience!

Thanks for watching. PM responses are welcomed, as our WiFi is, well, iffy.
Wally

[runfiverun]

I prefer regular lube grooves over t/l the body where it grabs the rifling is a bit stronger it seems to me.
plus you can vary the amount of lube you use.

[BABore]

What 45-70 are you planning to shoot this boolit in? Have you slugged the bbl and done a chamber cast and/or pound slug?

I ask because most 45-70's have a fairly short throat if one at all. The bore diameter is also around 0.449 to 0.452. Your dimensions above the crimp groove are more in line with a 450 Marlin throat than a typical 45-70. Seat a plain based 458 bullet or boolit backwards at 0.110 off of the case mouth to see if it will chamber. Most 45-70's will only handle around 0.040 to 0.060" of front band before the ogive begins. If this boolit happens to be for a Marlin, the max COAL will be around 2.55". This can be tweaked slightly through a little home smithing. A long nose with a 70% meplat may cause feeding issues. Please don't take any offense if all of this doesn't apply.

I would choose traditional lube groove with the choice of more lube grooves over just 1 or 2.

[Lloyd Smale]

listen closely. BaBore really knows what it takes to make a good bullet.
What 45-70 are you planning to shoot this boolit in? Have you slugged the bbl and done a chamber cast and/or pound slug?

I ask because most 45-70's have a fairly short throat if one at all. The bore diameter is also around 0.449 to 0.452. Your dimensions above the crimp groove are more in line with a 450 Marlin throat than a typical 45-70. Seat a plain based 458 bullet or boolit backwards at 0.110 off of the case mouth to see if it will chamber. Most 45-70's will only handle around 0.040 to 0.060" of front band before the ogive begins. If this boolit happens to be for a Marlin, the max COAL will be around 2.55". This can be tweaked slightly through a little home smithing. A long nose with a 70% meplat may cause feeding issues. Please don't take any offense if all of this doesn't apply.

I would choose traditional lube groove with the choice of more lube grooves over just 1 or 2.

[btroj]

You have been given good advice by a couple guys who know. Listen carefully to what they say, then move forward.

[Walstr]

What 45-70 are you planning to shoot this boolit in? Have you slugged the bbl and done a chamber cast and/or pound slug?

I ask because most 45-70's have a fairly short throat if one at all. The bore diameter is also around 0.449 to 0.452. Your dimensions above the crimp groove are more in line with a 450 Marlin throat than a typical 45-70. Seat a plain based 458 bullet or boolit backwards at 0.110 off of the case mouth to see if it will chamber. Most 45-70's will only handle around 0.040 to 0.060" of front band before the ogive begins. If this boolit happens to be for a Marlin, the max COAL will be around 2.55". This can be tweaked slightly through a little home smithing. A long nose with a 70% meplat may cause feeding issues. Please don't take any offense if all of this doesn't apply.

I would choose traditional lube groove with the choice of more lube grooves over just 1 or 2.

BABore; Sorry for omissions.. Yes, my 2003 Marlin 1895GS rifling slugs out @ .4595"-.460" with.452" Bore [typo in orig. submission]. My throat seemed larger than 'normal', Throat Length as slugged: .069” to beginning of throat taper.

With a case length of 2.083", the 'slug' shows rifling begins approx. .160" from the case mouth. This Lyman 457193 front band is too far back for roll crimp & too short for much case variance using my Lee FCD. This is the main reason for designing a better boolit.

I've loaded & fired C.O.A.L. rounds of 2.0585" max. with success, so I feel I should consider this dimension regarding bullet design to minimize unnecessary "jump" into the rifling.

Current Meplat of 54% from my Lyman 457193 mould, is [I've read] too small for my hunting needs (deer & feral hogs in Wisconsin & Florida, USA), which will most likely not extend past 200yds. The Lyman 457193 nose 'base' dia. is approx .442" which I feel is too small to properly guide/stabilize bullet entry into my bore.

Many seem to choose using a Gas Chk'd bullet design, but I'd rather skip that process & keep my velocities within the limitations of using Plain Base designs. I'm finding White Label Delux Xlox tumble lube products work as advertised up to 1400+ FPS so far, so in keeping with its simplicity (two applications), I think I desire a "tumble lube" design for my new bullet, and adjust velocity for optimal accuracy & barrel condition, i.e. NO leading. All shooting to date is using IMR-3031.

Based upon my experience in the electric power industry, the optimal pressure drop in a steam turbines' rotating steam seal results from forcing the gas path to change 180 deg. from 2000 psig internal pressure to the atmosphere, over a series of 20+ sharp edged 'fingers' on the rotating shaft that mesh with the turbine housing. So theoretically I see this application might translate to many narrow lube grooves. However typical cast bullet designs seem to favor large bands within the case, to provide maximum stability whilst maintaining minimal grooves for containing lube.

My learning curve has been rather steep & exciting since I got into this Boolit World last February. This educational endeavor is good medicine for my suspected AADD! lol Your time & expertise, responding to my quandary, is much appreciated.

Best regards,

Wally

p.s. One's learned advice can only offend those who believe their ignorance has limits.

[BABore]

BABore; Sorry for omissions.. Yes, my 2003 Marlin 1895GS rifling slugs out @ .4595"-.460" with.452" Bore [typo in orig. submission]. My throat seemed larger than 'normal', Throat Length as slugged: .069” to beginning of throat taper.

With a case length of 2.083", the 'slug' shows rifling begins approx. .160" from the case mouth. This Lyman 457193 front band is too far back for roll crimp & too short for much case variance using my Lee FCD. This is the main reason for designing a better boolit.

I've loaded & fired C.O.A.L. rounds of 2.0585" max. with success, so I feel I should consider this dimension regarding bullet design to minimize unnecessary "jump" into the rifling.

Current Meplat of 54% from my Lyman 457193 mould, is [I've read] too small for my hunting needs (deer & feral hogs in Wisconsin & Florida, USA), which will most likely not extend past 200yds. The Lyman 457193 nose 'base' dia. is approx .442" which I feel is too small to properly guide/stabilize bullet entry into my bore.

Many seem to choose using a Gas Chk'd bullet design, but I'd rather skip that process & keep my velocities within the limitations of using Plain Base designs. I'm finding White Label Delux Xlox tumble lube products work as advertised up to 1400+ FPS so far, so in keeping with its simplicity (two applications), I think I desire a "tumble lube" design for my new bullet, and adjust velocity for optimal accuracy & barrel condition, i.e. NO leading. All shooting to date is using IMR-3031.

Based upon my experience in the electric power industry, the optimal pressure drop in a steam turbines' rotating steam seal results from forcing the gas path to change 180 deg. from 2000 psig internal pressure to the atmosphere, over a series of 20+ sharp edged 'fingers' on the rotating shaft that mesh with the turbine housing. So theoretically I see this application might translate to many narrow lube grooves. However typical cast bullet designs seem to favor large bands within the case, to provide maximum stability whilst maintaining minimal grooves for containing lube.

My learning curve has been rather steep & exciting since I got into this Boolit World last February. This educational endeavor is good medicine for my suspected AADD! lol Your time & expertise, responding to my quandary, is much appreciated.

Best regards,

Wally

p.s. One's learned advice can only offend those who believe their ignorance has limits.

You have a long throat for a Marlin. You groove and bore dims look to be on the high side as well.

It may not be possible on Dan's design software, but the best nose profile is a full diameter nose diameter above the crimp groove where the ogive starts immediately at the intersect. The ogive radius is such the it contacts the start of the rifling. The full diameter start of the ogive should be just at or slightly below the desired sizing diameter so that it never gets sized.

Bore ride nose get tricky as they must be near perfect and give you no wiggle room if wrong.

[runfiverun]

you can partially adjust the bore ride section with an alloy change.
read the part about the ogive change for the throat again if you do size this area it changes the relationship and you lose accuracy.
I have one design in particular that if this area is touched I just throw the whole boolit back even if I have gas checked and lubed it.
it is a waste of time for me to even shoot them.