How do you crimp an all copper bullet. I am trying to load some barns 275gr.
First I tried to load like the lead copper bullets.
1. Use expander die just enough to flair case mouth
2. Use seating die seat bullet at 2.26
3. Use taper crimp die set about 1/8 taper to the case
This causes the bullet to be loose but it will not come out kinda like a rimfire bullet.
The next attempt I removed the expander die and it had the same affect of a rimfire bullet.
The next attempt I removed the expander die and the taper crimp die.
The bullet looked good and seemed solid. I firmly taped it nose down on the table and no movement. Then I used the thunk test and it passed. Then I fed it out of a clip and the bullet jumped forward from 2.26 to 2.28
What am I doing wrong and how can I fix it.
Its getting frustrating.
I have had the same problem and mentioned it in a post a while ago. The problem is the mass of the bullet is great enough to be pulled from the case due to the bolt velocity during chambering. Much like a bullet puller would do. Currently I expand the case mouths for .452 bullets, but not for .451 or as with the Montana Gold — .4505. I do not flare the mouths. If you set up the Hornady dies correctly, the bullet should start straight. Maybe chamfer the inside of the case mouth, but only slightly because this is where the headspace is occurring. I crimp in the crimp groove at the rearmost portion — trying to minimize the jump. A draw back of seating the bullet out as far as we can, lessens the amount of bullet in the case — thereby reducing the amount of friction to move the bullet forward. When I use the 300 gr. Remington sized to .452 and seated to the crimp groove — I do not get any bullet movement. Just a note — while chambering factory loads to test magazines, ect. — even those bullets will move forward the 2nd and 3rd time they where chambered.
Try not to get frustrated, this is a labor of love, wanting something the factory can’t give us, accuracy, down range energy, and of the all mighty dollar and we like that, right?
Solids are a bit of a problem, but Siringo has it solved and is the easiest way to go.
A couple of other suggestions are to bond the bullet to the case. The military does this with all their small arms ammo for waterproofing and bullet pull purposes (they seal the primers too). They use a gum in the case mouths. The closest thing I have used is the gum product that tree doctors use, to scab over a severed limb; most garden stores carry it, better call ahead though. It is applied by using a pipe cleaner and better let the gum set up after crimping. I however am quite lazy and bell the cases as much as I can and then, after seating the bullet I use red Loc-Tite (Just because I have a ton of it around the shop, other colors/types may certainly be useful), and then crimp (With my hunting ammo, I seal the primers with the same product). By using a drop on a tooth pick, capillary action will suck the drop into the case and totally around the bullet, experiment with the size of the drop. There are some things to consider though. First you have to let the Loc-Tite dry, 24hrs, and second, because of the extra bullet pull you’ll have to back off of the powder some. BUT, and this is a big “but”, that extra bullet pull burns the powder so efficiently that it will allow you to use slower powders, thus lowering the pressures, thus allowing you to bring the pressures back up and thus you’ll see much higher speeds (‘lil gun is very useful and I’ve even burned blue dot very successfully, but if speed is the goal, slower powders are the trick. Keep the pressures safely up, if you don’t want to see sooting). Of course, safe reloading practices apply; sneak up on the powder charge, looking for pressure signs all along the way. All this is unnecessary on lead based bullets as enough tapper crimp can be applied, unless of course, you want to use the slower powders. The Loc-Tite trick seems to cause more bullet pull than even a roll crimp (something we can use on the 450), which is a really a good thing, in my view, that is, if you are watching for excessive pressure signs. One other problem is, with all that excessive belling, you may want to extend case life by annealing, I do this regardless. I myself do this by sinking my de-primed cases into a cake pan of ice water about half way up the case body (keeping the heat away from the bases as you could see case head separation, a bad thing), then with a torch, propane is fine, heat them up to red hot and then knock them over, the water will instantly cool the cases and bingo, annealed cases.
Regarding neck tension — I have been playing around with various techniques/bullets tonight and despite what I do, I still get some bullet movement upon chambering. The only exception is when a crimp groove is present to lock into. But even then, repeated chamberings came move the bullet forward.
However, an extra step that really helps to minimize this is to clean the inside of the case neck after the case has been sized and expanded. That will remove any trace of case sizing lubricant or powder residue that could lessen neck tension. Do this even after using a case polisher. I used denatured Alcohol on a swab. Also, depending on the bullet, I want to have between .002 and .003 inches of neck tension (inside case mouth is that much smaller the bullet).
I have done so much testing the past 2 days that my right hand is sore from screwing and unscrewing dies in and out of the press.
No mater what I do I can not keep the barns bullet from moving. I have done all that you listed above and more. I took cleaning the case one step farther, I used 150grit sandpaper to rough the inside of case just one turn not to remove much material, that helped a little but very little. I have been getting about the same neck tension as you Siringo so i increased it to .006 by using the taper crimp die before loading the bullet, but it was no help. The taper crimp can only kiss the brass or it will dent the barns bullets with decrease the neck tension.
The best results I have had came from peening the case around the bullet.
I got this idea from some 7.62×25 pistol bullets i have for my cz52. The casing has three peen marks half way down the neck I suspect to increase reliability for the submachine gun the round was made for. For people that are unfarmiliar with the 7.62×25 it is a bottle neck pistol bullet.
Following the idea of the peen marks I took a small nail set and put 3 peen marks on one case and 4 on another. The first cartridge started at 2.262
after the first chambering it jumped to 2.267 second 2.269 third 2.270 fourth 2.271 faith 2.274 sixth 2.277 The second cartridge with 4 peen marks started at 2.260 after the first champering it went to 2.263 second 2.264 third2.265 fourth 2.265 faith 2.266. The down side to this is that I have no way to be consistent with the depth and location of the dents. If someone knows how please speak up.
The last attempt to decrease bullet pull I used was to set the bullet deeper to catch the crimping groove. I didnt want to increase the distance the bullet had to jump to get to the lands or decrease case capacity but Im at the end of my ideas. I seated the bullet to 2.215. The outside of the case mouth before the bullet was .476 after bullet seated .479 after taper crimp .476 . The first chambering it went to 2.225 second 2.231 third 2.240.
As a reference I used a factory round and tested it too. It started at 2.234
after the first chambering it was 2.242 second 2.250 third 2.258. about the same as when I seated it to the crimp grove.
I then checked case capacity with H110 with the 275gr Barnes set to a depth of 2.215. First i weighed the case with seated bullet 445.7gr then added the powder 484.6gr. This gave me a difference of 38.9gr and confirmed after powder measured alone.
To be clear on the crimp. you cannot crimp ( roll crimp etc.) the 450 Bushmaster. This cartrige headspaces on the case mouth.
That’s right, it does headspace on case mouth. The factory die set includes a roll crimp with the seating die and a separate taper crimp die. I’ve been using the taper crimp on the smooth sided bullets, however I have some bullets with a canulare – canlura – canulalure- whatever, groove, and I have put a slight roll crimp on those.
Apply sharpie marker to the outside of the bullet and case.
Chamber and then extract.
The sharpie marker will get removed from the offending areas.
The offending area is the case at the base of the bullet.
The factory case diameter at the mouth with a seated bullet is .478″ with the case diameter .481″ at the base of the bullet. I was able to crimp the 284 cases to match the factory .478 diameter, but at the base of the bullet the 284 case swells to .489″. That’s where it was hanging up.
This is THE classic “short of headspace” symptom.
If you drop the cartridge into the chamber and let the bolt fly home, the kinetic energy stored in the bolt carrier group will SIZE the cartridge in the chamber.
If the same cartridge will NOT let the bolt close from a mag, that’s because you burned off some of that kinetic energy in getting the cartridge out of the magazine and around the corner into the chamber.
The 3/8″ or so of carrier is the locking/unlocking travel.
When you drop a 5.56 “field” gauge in a 5.56 barrel, that’s what you are supposed to see because the bolt should NOT close on a field gauge.
The pressure signs ALSO point to the case mouth getting crimped against the bullet.
Does the 450 headspace off the case mouth?
Ditto Randall, you are going in the exact same direction I am, but time will tell, once we read all the symptoms, we’ll be better able to diagnose the problem. And yes the head space is off the case mouth.