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JasonT
Guest
Those are some good ideas with the cutters - I think an abrasive wheel/stone is NOT the way to go as they wear down over a very short amount of time and require adjustment. Also, copper does not like to be abraded. It sort of "folds over" if you sand it. There are other cutter types I can investigate. I like the idea of carbide cutter of some sort, like a bur or a reamer. I still think HSS is the way to go with copper cutting. HSS can get sharper than carbide, so it "cuts" rather than "pushes."
I think I've got something figured out that would be similar to a WFT brass trimmer but have a simple solution for swapping out the various calibers. I'd guess it would be marketable around the price (+/-) of the WFT, with inserts for each additional caliber being some incremental cost after that.
I think a micrometer stop is going to add too much to the cost to be a viable solution. I also think it would cut down on simplicity and durability.
Keep the suggestions coming - I like to hear what people want and see if it can be worked into the design.
I think I've got something figured out that would be similar to a WFT brass trimmer but have a simple solution for swapping out the various calibers. I'd guess it would be marketable around the price (+/-) of the WFT, with inserts for each additional caliber being some incremental cost after that.
I think a micrometer stop is going to add too much to the cost to be a viable solution. I also think it would cut down on simplicity and durability.
Keep the suggestions coming - I like to hear what people want and see if it can be worked into the design.
Dusty Stevens
Hollow Point Dispenser
This is what im talking about:
http://www.pmatool.com/pma-micro-adjust-trimmer/
Not really a micrometer but ease of adjustment and spring loaded. And it uses an end mill to cut. You take this, put it in a benchtop box, motorize the cutter and itll sell for $500 easily. I actually trim and point bullets.
http://www.pmatool.com/pma-micro-adjust-trimmer/
Not really a micrometer but ease of adjustment and spring loaded. And it uses an end mill to cut. You take this, put it in a benchtop box, motorize the cutter and itll sell for $500 easily. I actually trim and point bullets.
Dusty Stevens
Hollow Point Dispenser
Its a case trimmer joe. Slick as owl snot on a linoleum floor. No wobble there but like i said its for cases
Dave Tooley
Active member
Suggestion from the guy who started making meplat trimmers a long long time ago. My trimmer did a good job using a cylinder section followed by a taper but starting out with ugly meplats bullets could wobble slightly until the majority of the meplat was cleaned up and cutting forces were balanced. Then it would settle down. It was more about perception than the final product. The only way to stop the wobble is to support the bullet in two places. You have to support the ogive close to the meplat and then the body to make everyone happy. Also understand you reach a point of diminishing returns very quickly. Over reaching complicates things and adds expense.
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JasonT
Guest
Dusty, I like the look of that device, and I may try to incorporate a locking threaded section for fine adjustment.
Dave, it's an honor to hear from you on here, and thanks for the suggestions - I really do appreciate wise words. I think you're right, the bullet should be supported close to the meplat to prevent runout/"wobbliness" at the cutter. I actually didn't think about that, so I'm glad you brought it up! I have modeled the system using .30 cal because that's what I shoot (Ftr-type stuff) - and I'm supporting the whole circumference of the bullet and letting it seat itself on its own ogive when it's @ .284" diameter. The hard part is that for some bullets that's pretty close to the tip, but for others it's very far (Berger Hybrid 230s for example). Do you think it would be safer to support all bullets at around .22"? I'm trying to keep the hole sizes in caliber equivalents for manufacturing's sake.
Just so everybody is aware, Nigel (Doc) from Applied Ballistics has mentioned to me that meplat trimming actually harms the balance of the bullets. Any thoughts or opinions?
Dave, it's an honor to hear from you on here, and thanks for the suggestions - I really do appreciate wise words. I think you're right, the bullet should be supported close to the meplat to prevent runout/"wobbliness" at the cutter. I actually didn't think about that, so I'm glad you brought it up! I have modeled the system using .30 cal because that's what I shoot (Ftr-type stuff) - and I'm supporting the whole circumference of the bullet and letting it seat itself on its own ogive when it's @ .284" diameter. The hard part is that for some bullets that's pretty close to the tip, but for others it's very far (Berger Hybrid 230s for example). Do you think it would be safer to support all bullets at around .22"? I'm trying to keep the hole sizes in caliber equivalents for manufacturing's sake.
Just so everybody is aware, Nigel (Doc) from Applied Ballistics has mentioned to me that meplat trimming actually harms the balance of the bullets. Any thoughts or opinions?
Dave Tooley
Active member
You have to engineer it for the worst case. That being tangent ogive bullets and the secant bullets fall where they will. Because of the distance involved I don't think it will an issue supporting the body and then the ogive as far forward as is practical. That would be better than what I did which worked. As far as "harms the balance", not sure of the definition there. If you have a good bullet and uniform the meplat I know inflight yaw is reduced which makes the BC's more uniform. Does that equate to improved accuracy? Not if all bullets fly the same. Most don't.
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JasonT
Guest
Ok, it sounds like I'm on the right track for bullet support then.
According to Doc, the bullets are balanced when they come out of the presses. I'm inclined to believe him due to his experience, but I'm certainly not ready to close the book on it yet.
If all of you do see real-world benefits from trimming and pointing, then I'm all for creating a trimming product that would simplify the whole process.
Jason
According to Doc, the bullets are balanced when they come out of the presses. I'm inclined to believe him due to his experience, but I'm certainly not ready to close the book on it yet.
If all of you do see real-world benefits from trimming and pointing, then I'm all for creating a trimming product that would simplify the whole process.
Jason
Dusty Stevens
Hollow Point Dispenser
Just look at a meplat under a microscope. Then youll see why trimming improves bc. And trimming .003 off of one side of the meplat will not unbalance a bullet- if it did how would you measure it before or after anyway?
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Mozella
Guest
I recently had a conversation with Berger about the ugly meplat on their 6mm 105gr hybrid bullets. These bullets have a particularly uneven tip with one side significantly different from the other. The tips of the 105gr VLD Hunting bullets look much more uniform. The technician (or maybe it was the guy who sweeps the floors, I don't know) explained to me that the heavier target jacket on the hybrid target bullet is more difficult to form properly than the thinner jacket used on the VLD Target bullet and that explains the difference; makes sense to me.
The Berger hybrid bullet is asymmetrical about the longitudinal axis and this asymmetry can easily be seen by the naked eye. Since, as far as I know, these bullets aren't balanced after manufacture by adding teeny, tiny tire weights, I can only assume that they are NOT in balance when they come out of the press. Of course, the imbalance can be measured, but certainly not with any equipment I have in my reloading room, so I can't prove it directly. But I don't see how they could be as well balanced as the Hunting version with the more perfect meplat.
In addition the asymmetrical shape of the hybrid meplat should produce a certain amount of inconsistency from an aerodynamic point of view. Trimming the meplat will make the bullet less pointed and result in a lower B.C.;however, any reduction in performance because of the increased drag would be, in theory, more than offset by increasing the uniformity and (it is hoped) improving precision at the target.
Unfortunately, actually measuring any actual increase in performance by meplat trimming isn't easy. Nevertheless, I find it hard to believe that it doesn't help the Berger 105 hybrid bullets in particular. The fact that I won last month's 600 yard BR match after trimming the Berger hybrid bullets is a data point, but it certainly isn't rock solid proof one way or the other. Nevertheless, I will continue to trim them because it's hard for me to believe it doesn't help in spite of a decrease in B.C. Having said all that, I'm not ready to predict a win in this month's BR match even though I'll be using the same trimmed bullets which worked well last month.
On the other hand, I wonder if meplat trimming will offer much measurable improvement if a particular bullet has a perfect meplat as it comes out of the factory forming die. It could very well be a waste of time or perhaps even a tedious routine which actually hurts performance.
But if trimming is a necessary step involved with bullet pointing, a discipline I have yet to practice and know little about, then I'm all for a more user friendly trimming equipment.
Dave Tooley
Active member
Balance, a vague term. Trimming a few thousandths off the meplat can't change the balance but can improve flight characteristics when comparing bullet to bullet performance. For a target shooter that means something. I've seen Dopplar data that shows bullets doing funny things as they go down range. Hornady's new ELD line of bullets came about because of what they discovered shooting through Dopplar. Very subtle changes in the tip shape due to heat.
Dusty Stevens
Hollow Point Dispenser
Ogive lengths vary so much youd have to index off of it instead of the base
Dave Tooley
Active member
The length of the bearing surface and boat tail have nothing to do with the airflow over the frontal area of the bullet. You have to index off the ogive.
The test I did for Sierra showed an average of a 2% decrease in BC when meplats were trimmed. A 2-5% increase in BC when I installed Sierra's green tips. That was from .224's to .338's.
We're talking about BC ES. As I said you can have less than perfect meplats and the bullets will shoot fine. It's about bullet to bullet consistency. That's where a bullet with a tip inserted has a bit of an advantage. All this applies to high BC bullets at distance.
The test I did for Sierra showed an average of a 2% decrease in BC when meplats were trimmed. A 2-5% increase in BC when I installed Sierra's green tips. That was from .224's to .338's.
We're talking about BC ES. As I said you can have less than perfect meplats and the bullets will shoot fine. It's about bullet to bullet consistency. That's where a bullet with a tip inserted has a bit of an advantage. All this applies to high BC bullets at distance.
J
JasonT
Guest
Mozella, thanks for such a detailed and thoughtful response - I will most definitely make the meplat trimmer after hearing that! Maybe you'll get an extra little gift with your prototype pointing die 
Dusty, Bill, and Dave - much thanks to you as well. I appreciate you sharing your knowledge as it will most definitely improve the final design.
I will definitely be indexing off of the Ogive. Yes, in a textbook, the best uniformity of OAL would be gotten if indexing off of the base. But in practice, that's a long and arduous process to set up the device for every bullet. In addition, indexing off of the ogive serves 2 functions. It provides a relatively consistent "zero" and it also supports the bullet close to the tip, which Dave mentioned was very important for getting good results.
Just as an update to all, I've started work on the initial prototype of the meplat trimmer as of last night. It should be very similar to the easy and simple setup of the WFT, but it will have quick-change aspects that would allow the same body to work for multiple calibers. Overall it would save money to the end user - instead of buying a whole new unit for each caliber, they'd just buy a replacement insert/head (not 100% sure which I'd rather do yet.)
If any kind souls feel the desire to help the development of this product, I'd appreciate you sending me a few of your favorite bullets so I can finalize the dimensions for each insert/head. If I make it too deep, you'll lose your bullet. And if I make it too shallow, there won't be enough support. I wish I could afford to buy all of the different bullets, but sadly, I can't. PM me if you're so inclined - thanks!
Thanks again to everybody! I still welcome all suggestions!
Dusty, Bill, and Dave - much thanks to you as well. I appreciate you sharing your knowledge as it will most definitely improve the final design.
I will definitely be indexing off of the Ogive. Yes, in a textbook, the best uniformity of OAL would be gotten if indexing off of the base. But in practice, that's a long and arduous process to set up the device for every bullet. In addition, indexing off of the ogive serves 2 functions. It provides a relatively consistent "zero" and it also supports the bullet close to the tip, which Dave mentioned was very important for getting good results.
Just as an update to all, I've started work on the initial prototype of the meplat trimmer as of last night. It should be very similar to the easy and simple setup of the WFT, but it will have quick-change aspects that would allow the same body to work for multiple calibers. Overall it would save money to the end user - instead of buying a whole new unit for each caliber, they'd just buy a replacement insert/head (not 100% sure which I'd rather do yet.)
If any kind souls feel the desire to help the development of this product, I'd appreciate you sending me a few of your favorite bullets so I can finalize the dimensions for each insert/head. If I make it too deep, you'll lose your bullet. And if I make it too shallow, there won't be enough support. I wish I could afford to buy all of the different bullets, but sadly, I can't. PM me if you're so inclined - thanks!
Thanks again to everybody! I still welcome all suggestions!