Bullet Annealing

[barnesuser28]

Bullet bumper, in terms of bullet jacket, or composition of monometal bullets is there a way to measure hardness? If so is there a level of "hardness" you prefer? The Barnes X bullets were "soft" and fouled badly at times like you said. After that some got "harder" and did not expand well. We thought at one time giving them a bit more hollow point might give more reliable expansion. So we chucked them in a lathe and drilled them out a bit. From the same box came those that the copper just peeled easily from, and those we could not cut at all. One of the younger members of the group shot a few deer with them, the "soft" ones had large wound channels the "hard" ones had pass throughs. These were 338 bullets. We "inferred" hardness was the bigger issue than the hollow point. From some of the younger guys Tikkamike, and Riley Barnes may have fixed this issue. The question is if Riley was to experiment with hardness/annealing is there a way to measure it vs backtracking from the results? Thanks for your experience!

I pulled the tips from a .338 280 grain LRX and a .338 210 grain TTSX and the INSIDE diameter of the meplat measured .95 for both. The HUGE meplat inside diameter is the main reason i think the tipped versions of the X bullet is greatly improved over the tsx and original x bullet with their tiny meplat holes.

I think based on my experience with Barnes so far thy have fixed the hardness problem.

One more thing, when i toured their factory, they said before the tips were installed they gave the bullets a light annealing to relieve the work hardening of the copper going through the multiple forming dies, I think it also makes the hardness more consistant bullet to bullet, but they keep them hard enough that fouling isnt too much of a problem.

so its my thinking that if i anneal before the bearing surface the copper around the expansion cavity will be soft enough to expand at ridiculously low velocities.

Now all i have to do is figure out how to remove the tip without damaging it and to put it back in straight.

 

[elkaholic]

That is just crap. I am a bullet maker and annealing makes the jacket softer and tougher so it is " less " likely to fragment .
If a bullet has a lead core even if you only melt a fraction of the top edge of the core you have upset the balance of the bullet . The affect on accuracy could range from slight to catastrophic .
At a temp that does any useful annealing of gilding metal jackets some lead would surely melt.
You could anneal a solid mono metal bullet OK but there is no guarantee it's diameter would not change slightly . I am not sure I have not tested it.
A softer bullet means more fouling so why the hell do it anyway.

Being a bumper myself, I totally agree with bumper......Rich

 

[Bullet bumper]

That is a very complicated question .
You could measure the hardness of a mono metal bullet using a standard Brinell hardness test as the material is a solid.
Doing the same for a hollow thin jacket would be far more difficult as the jacket may give as the test is being done .
Mono metal bullets like Barnes X are usually cast first into a blank with a segmented front and then swaged to shape in a hydraulic swaging press.
The strength of the press controls how hard the copper alloy can be and still do a proper swaging job and not break the press or die .
I don't make solid bullets but I guess that bullet makers most likely responded to complaints about fouling so they went to harder material and stronger press system to try and fix that.
Trouble is the very hard bullet tends to not let the rifling engrave it as well as the softer one so that can cause extra wear and sometimes pressure but many have grooves and driving bands to reduce this effect.
I think that mass production could be a cause of variation in material hardness as different stock is introduced into the process and even multiple stations all making a slightly different batch that all get mixed together before packing.
To precisely control the annealing of a solid bullet it would take some custom gear similar to a rotary case annealer and you would have to use a Brinell hardness tester after they cooled right down . A Webster or other portable hardness tester might work .
In the end I don't think there is much to gain by annealing any bullet . The physical construction also has a lot to do with terminal ballistics and annealing will not change that to any great degree .
If I was going to do it after the bullet is annealed I would moly coat the bullet to reduce the extra potential for fouling with the softer solid bullet .
I think once you enter the area of trying to improve a solid bullet after it is made you are saying that it is not suitable to what you want in the first place .
Maybe look at other designs , ballistic tips , core bonded etc. etc.
There is no specific hardness that I like in a jacket as they come they vary quite a bit anyway. The main thing is that during the point forming process that no splitting or excessive wrinkling on the ogive takes place . If that happens they are too hard.
Now you don't want a very soft jacket all over as it needs some spring back to eject properly out of the dies. So if a batch of jackets is too hard and starts splitting at the meplat then I only anneal about 1/3 of the length from the open end .
This is very rare to happen as most commercial jackets work ok as is.
With a core bonded bullet that is heat /solder bonded , the melting of the lead core leaves the jacket soft but it makes it a tougher bullet less likely to split the jacket on impact and again I would moly coat this kind of bullet . Commercial bullet makers don't use this process anymore it is too slow . They tend to use chemical bonding . So the jacket hardness will be what ever it is at the final stage of manufacture . Which will be harder than a heat bonded bullet like the Woodleigh Weld core was .
In conclusion if you make them softer , moly coat them and then you may get the advantage you are looking for without the drawback of extra fouling .

 

[HARPERC]

Bullet bumper,
Thanks, very helpful answer for me. Sitting here looking at some of the bullets I've recovered over the years, and getting a little clearer picture regarding the bullet to bullet variation. Thanks for your time!

 

[Bullet bumper]

No worries mate . I sounds to me that you are ready to make your own bullets from scratch . Rather than try and fix factory bullets.
Once you start making your own there is many ways to develop a custom bullet.
You can fit jackets inside jackets to form partitions . You can solder bond it in one section and not another if you want . You can bond the whole lot . Make a rebated boat-tail . It is even possible to seat ballistic tips in a point forming die . Make a big hollow point ( Protected Point ) or a nice spire point lead tip .
It's a lot more productive and satisfying than trying to fix factory bullets .
Start here Corbin Home Page
If things get bad you can get dies to make a jacketed bullet out of copper refrigeration tubing . The bigger the cal the bigger tubing you use.

 

[elkaholic]

Bumper, it sounds like we were "swaged in the same die"! I've been loading .264 jackets backwards in my .308's and also frontward gives a nice affect as well. I now punch a .120" hole in the jacket first which makes a kind of "semi partition" but it works very well. The hole lets the lead flow between the two cores and you can bond one or both. I was disappointed that Corbin quit handling the aluminum tips. The steel ones require more twist than you would think (for the same length). Good to hear from you....Rich

 

[Bullet bumper]

Bumper, it sounds like we were "swaged in the same die"! I've been loading .264 jackets backwards in my .308's and also frontward gives a nice affect as well. I now punch a .120" hole in the jacket first which makes a kind of "semi partition" but it works very well. The hole lets the lead flow between the two cores and you can bond one or both. I was disappointed that Corbin quit handling the aluminum tips. The steel ones require more twist than you would think (for the same length). Good to hear from you....Rich

Yes I think we are soul mates . I probably can't experiment as much as you can because I have to import most of my jackets and pay more for them .
However I have tried different ways to make a partition. Although not the hole punching idea . That sounds very interesting and new . I can see what you are saying about facilitating core bonding while still acting as a partition .
Down here we don't have the big game like the US does so I mainly only have a need for a standard core bonded core . I have dreams of taking a Cape buff with one of my bullets but I will never be able to afford that .
I am sure you are more advanced in bullet making than me as the US market is the home of bullet swaging and just so big and everything you want is easily available. 100% of what I know came from the US anyway . That is good for me as I have just learnt something new . Thanks mate .
I saw those aluminium tips some time back and was tempted to buy some . They are a good way of increasing the BC substantially .
The steel ones would be heavier and might move the centre of pressure and gravity , while making them longer also.
I have never tried them so I can only guess.

 

[elkaholic]

Yes I think we are soul mates . I probably can't experiment as much as you can because I have to import most of my jackets and pay more for them .
However I have tried different ways to make a partition. Although not the hole punching idea . That sounds very interesting and new . I can see what you are saying about facilitating core bonding while still acting as a partition .
Down here we don't have the big game like the US does so I mainly only have a need for a standard core bonded core . I have dreams of taking a Cape buff with one of my bullets but I will never be able to afford that .
I am sure you are more advanced in bullet making than me as the US market is the home of bullet swaging and just so big and everything you want is easily available. 100% of what I know came from the US anyway . That is good for me as I have just learnt something new . Thanks mate .
I saw those aluminium tips some time back and was tempted to buy some . They are a good way of increasing the BC substantially .
The steel ones would be heavier and might move the centre of pressure and gravity , while making them longer also.
I have never tried them so I can only guess.

Bumper....I think you are more advanced than you give yourself credit for! You sound pretty savy to me. You are correct on the steel tips. If you have marginal twist, moving the weight forward just a little (STEEL TIPS) makes a very accurate bullet no so good at all......Rich

 

[Bullet bumper]

This is interesting, i think if they are kept tip up like in the video then the lead will kinda bond itself to the jacket. i wonder how that would affect terminal performance.

Unfortunately melting the core dose not work like that. What happens is the molten metal will expand and then on cooling shrink back more at the centre far more than the sides . Leaving an uneven depression at the surfaces centre .
This depression has to be levelled out in the core seating process to restore good concentric form and hence good rotational balance .
You can't do that with the ogive already formed . You just end up with a depression in the core surface that is unreliably shaped. Some might be ok and some will not be as accurate as before .
Without a flux inside the jacket it will not bond to any useful degree. If the bullet is already chemical bonded then the heat may destroy that bond .

 

[elkaholic]

Unfortunately melting the core dose not work like that. What happens is the molten metal will expand and then on cooling shrink back more at the centre far more than the sides . Leaving an uneven depression at the surfaces centre .
This depression has to be levelled out in the core seating process to restore good concentric form and hence good rotational balance .
You can't do that with the ogive already formed . You just end up with a depression in the core surface that is unreliably shaped. Some might be ok and some will not be as accurate as before .
Without a flux inside the jacket it will not bond to any useful degree. If the bullet is already chemical bonded then the heat may destroy that bond .

Again, right on the money! You will also end up with some oxide material inside your jacket from the heating (likely)

 

[HARPERC]

Just enjoying the conversation, I'm listening as long as your talking. Thanks

 

[elkaholic]

Just enjoying the conversation, I'm listening as long as your talking. Thanks

Now why can't my wife be like you!!........Rich

 

[Bullet bumper]

Again, right on the money! You will also end up with some oxide material inside your jacket from the heating (likely)

Yes mate , I forgot about that .
I have not spoken to my wife in 20 years because I don't like to interrupt !

 

[elkaholic]

Actually, my wife is pretty cool but a little humor doesn't hurt