how do you crimp a case?
- Thread starter JTF#
- Start date
Buy a reloading manual and READ it twice. The seating die also crimps. I have 2 ways to set up a new die. Unscrew the seating stem all the way, screw in the die with a loaded (factory) round in the press until it gets hand tight. Drop the ram and add 1/4 turn. Raise the ram and screw down the seating stem until it touches the loaded round. Try seating a bullet in a resized empty case (you have a bullet puller...right?) Adjust as needed.
The other method with no loaded round also starts off with backing off the seater stem and screwing the die in until it almost touches the shell plate. Try a resized case with no bullet and see if it crimps the top of the case. It then is a matter of adjusting for seating.
In my 71/84 with lead bullets I only "crimp" enough to straighten out the bell from expanding the case mouth to accept the cast bullet without shaving the lead.
The other method with no loaded round also starts off with backing off the seater stem and screwing the die in until it almost touches the shell plate. Try a resized case with no bullet and see if it crimps the top of the case. It then is a matter of adjusting for seating.
In my 71/84 with lead bullets I only "crimp" enough to straighten out the bell from expanding the case mouth to accept the cast bullet without shaving the lead.
- Location
- Alta/Sask Border Country
I think I may have been doing something wrong:
I have a Lee setup, with 4 dies. the fourth is a 'factory crimp' die. In that type of setup does the seating die not crimp, since there's a specific die for it?
Also, my instructions called for running the ram up to top, and setting the seating die to 'almost touching'. My first round ended up fully in the brass (while building a dummy, luckily), and I ended up backing out the stem to the appropriate seating depth.
I have a Lee setup, with 4 dies. the fourth is a 'factory crimp' die. In that type of setup does the seating die not crimp, since there's a specific die for it?
Also, my instructions called for running the ram up to top, and setting the seating die to 'almost touching'. My first round ended up fully in the brass (while building a dummy, luckily), and I ended up backing out the stem to the appropriate seating depth.
There are different types of crimps.
Pistol rounds, if you look up in the seat die will begin to taper in at a certain point. Depending on how high or low you set the die itself will determine the crimp ( use the turn knob part to get the seating depth to what you want ).
I'm not sure if all rifle dies also do the above mentioned crimp ( think it is referred to as a roll crimp ). Although for rifle rounds you can also buy a 'factory crimp' die which is a collet that presses the brass in at the tip. Some rifle cases are really soft and a small bit of factory crimping may be necessary to have the rounds not easily be pushed into the case.
Rifle reloading is one area where I am still very new to the subject so feel free to correct me on those bits if I am wrong.
As for setting up your load dies I always follow this process.
1: Get your shell holder into the ram, and put one case with a flared mouth on the shell holder, now fully raise the ram.
2: Screw in the seating die until it touches the end of the brass, note that this means that the crimping part of the seating die has now just met with the flared case which is wider than the desired finished product.
2.1: Lower the ram and take a tip, drop it in the top of the case. Raise the bullet seating depth adjuster knob ( the thing in the middle of a lee seater die ). Now bottom out your press again and screw in the bullet seater knob so that it touches the bullet top.
3: Drop the ram down and turn your seating die 2-3 full turns further in and lock it in place there. ( Now any further brass that goes in will receive the roll crimping )
4: you will need to make adjustments with the seating knob to turn it in to the desired length from here, but this should have it so that it won't be dropping your tips in too deep off the hop.
This can be simplified if you have a dummy round loaded with the desired amount of crimp as you bottom out the ram, screw the die and bullet seater knobs in till they are tight on the dummy and you are good to go with some small adjustments.
Edit:
To those starting with the dies 'almost touching' Im guessing those dies to not have a roll crimp so all that matters is the seat depth gauge; if you do this with a roll crimp die you may end up with some messed up cases.
Pistol rounds, if you look up in the seat die will begin to taper in at a certain point. Depending on how high or low you set the die itself will determine the crimp ( use the turn knob part to get the seating depth to what you want ).
I'm not sure if all rifle dies also do the above mentioned crimp ( think it is referred to as a roll crimp ). Although for rifle rounds you can also buy a 'factory crimp' die which is a collet that presses the brass in at the tip. Some rifle cases are really soft and a small bit of factory crimping may be necessary to have the rounds not easily be pushed into the case.
Rifle reloading is one area where I am still very new to the subject so feel free to correct me on those bits if I am wrong.
As for setting up your load dies I always follow this process.
1: Get your shell holder into the ram, and put one case with a flared mouth on the shell holder, now fully raise the ram.
2: Screw in the seating die until it touches the end of the brass, note that this means that the crimping part of the seating die has now just met with the flared case which is wider than the desired finished product.
2.1: Lower the ram and take a tip, drop it in the top of the case. Raise the bullet seating depth adjuster knob ( the thing in the middle of a lee seater die ). Now bottom out your press again and screw in the bullet seater knob so that it touches the bullet top.
3: Drop the ram down and turn your seating die 2-3 full turns further in and lock it in place there. ( Now any further brass that goes in will receive the roll crimping )
4: you will need to make adjustments with the seating knob to turn it in to the desired length from here, but this should have it so that it won't be dropping your tips in too deep off the hop.
This can be simplified if you have a dummy round loaded with the desired amount of crimp as you bottom out the ram, screw the die and bullet seater knobs in till they are tight on the dummy and you are good to go with some small adjustments.
Edit:
To those starting with the dies 'almost touching' Im guessing those dies to not have a roll crimp so all that matters is the seat depth gauge; if you do this with a roll crimp die you may end up with some messed up cases.
- Location
- The Conservative part of Ontario
Lee dies incl. factory crimp die.
With the factory crimp die in your die set, you do not need to crimp with the seating die, just install the factory crimp die, and run the completed cartridge into it until the ram pushes the collet up to it's seat. Done! It will crimp even if the bullet you are using does not have a crimp groove, or if some cases are slightly longer than others. If you are using it, and doing this, look closely at the completed round. The crimp may be hard to see.
Your seating die still possess the ability to crimp. I think the guys above explained that. But I'll go a bit further.
The cavity that you push your case into when seating a bullet has a taper at the top that crimps. If you do not push it in far enough you don't get a crimp. You may have to back out your seating stem a ways to allow the case in far enough and still get the Over All Length (OAL) you want. Otherwise your bullet will be seated too deeply. You want a LIGHT crimp. Too much will buckle the case and you will end up with a bullet looser than no crimp at all.
In this rather blurry image (lyman die pictured couldn't find a Lee pic, but they are similar) the crimping taper is located about opposite the number 7. As you can see, if you set your bullet seating stem (item 8) low enough, and your die body (item 6) high enough in the press, it's possible to easily seat a bullet without a crimp.
If you have a completed cartridge, place it in the press, and raise it gently into the die. Now back out your seating stem until the handle on your press stops lowering. This is the contact point for crimping. Now back out your die until this occurs at end of ram stroke, turn it back in about a quarter turn and lock it. If you apply slight pressure at this point you may get the crimp dead on. or you may have to play with the two adjustments. The trick is to study the pics and understand just what you are accomplishing. Once this becomes clear it's easy.
It's important to note that using the seating die to crimp ALL cases MUST be the same length.
Other crimping / seating tricks:
Get ALL the lube off of your dies, including inside the case neck for best neck tension.
Chamfer inside the case necks VERY lightly. Leave as much meat as possible for the crimp to act on. You just want to lightly remove the square edge so it does not scrape your bullet as it is being seated.
With the factory crimp die in your die set, you do not need to crimp with the seating die, just install the factory crimp die, and run the completed cartridge into it until the ram pushes the collet up to it's seat. Done! It will crimp even if the bullet you are using does not have a crimp groove, or if some cases are slightly longer than others. If you are using it, and doing this, look closely at the completed round. The crimp may be hard to see.
| Lee Factory Crimp Die crimps your bullets in place the same as factory ammo. A collet gently, but firmly squeezes the very end of the case into the crimping groove, exactly the same as factory ammo.
|
Your seating die still possess the ability to crimp. I think the guys above explained that. But I'll go a bit further.
The cavity that you push your case into when seating a bullet has a taper at the top that crimps. If you do not push it in far enough you don't get a crimp. You may have to back out your seating stem a ways to allow the case in far enough and still get the Over All Length (OAL) you want. Otherwise your bullet will be seated too deeply. You want a LIGHT crimp. Too much will buckle the case and you will end up with a bullet looser than no crimp at all.
If you have a completed cartridge, place it in the press, and raise it gently into the die. Now back out your seating stem until the handle on your press stops lowering. This is the contact point for crimping. Now back out your die until this occurs at end of ram stroke, turn it back in about a quarter turn and lock it. If you apply slight pressure at this point you may get the crimp dead on. or you may have to play with the two adjustments. The trick is to study the pics and understand just what you are accomplishing. Once this becomes clear it's easy.
It's important to note that using the seating die to crimp ALL cases MUST be the same length.
Other crimping / seating tricks:
Get ALL the lube off of your dies, including inside the case neck for best neck tension.
Chamfer inside the case necks VERY lightly. Leave as much meat as possible for the crimp to act on. You just want to lightly remove the square edge so it does not scrape your bullet as it is being seated.
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- Location
- The Conservative part of Ontario
The factory crimp die offers advantages for:
Not having to fuss with getting the crimp just right with a standard die set (easy once you are used to it).
The ability to crimp a few rounds without readjusting your dies to do so.
Say you are a bolt gun user who usually does not crimp. (You do not have to crimp you know) but you want to for some reason. You don't have to change your die settings, just screw in the factory crimp die and crimp the number you want.
IMO
Crimping under SOME circumstances gives better ignition, and better accuracy. BUT the crimp must be perfect and uniform from one cartridge to the next to do so.
In most circumstances for a bolt gun guy, you're better not to crimp.
Using a tube mag for hunting, or a very heavy recoiling cartridge you should crimp to avoid bullet movement during recoil, or from continued loading and unloading against the tube mag spring.
Even there, if you are a guy that goes out with his lever gun and shoots off every cartridge he loads in the tube every time you go out, you MAY get away with not crimping. But as a new reloader, probably not, it takes time to get neck tension just right.
Not having to fuss with getting the crimp just right with a standard die set (easy once you are used to it).
The ability to crimp a few rounds without readjusting your dies to do so.
Say you are a bolt gun user who usually does not crimp. (You do not have to crimp you know) but you want to for some reason. You don't have to change your die settings, just screw in the factory crimp die and crimp the number you want.
IMO
Crimping under SOME circumstances gives better ignition, and better accuracy. BUT the crimp must be perfect and uniform from one cartridge to the next to do so.
In most circumstances for a bolt gun guy, you're better not to crimp.
Using a tube mag for hunting, or a very heavy recoiling cartridge you should crimp to avoid bullet movement during recoil, or from continued loading and unloading against the tube mag spring.
Even there, if you are a guy that goes out with his lever gun and shoots off every cartridge he loads in the tube every time you go out, you MAY get away with not crimping. But as a new reloader, probably not, it takes time to get neck tension just right.
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Just to add re crimping with a standard seating die. All cases MUST be the same length. If a longer case is inserted, over crimping will happen and possibily push the neck into the shoulder and collapse it. The advantage of the Lee factory drimp die is that it is not case length sensitive.
- Location
- The Conservative part of Ontario
Thanks for that, I forgot so edited it in.
Lee may make one for you ,but be prepared to wait quite awhile for it. Not exactly a huge demand for that round. Crimping with your seating die is not a big deal if you adjust it right. It can be done as a seperate step at the end by raising your seating stem and lowering the die a bit. It has been done for years like that.
