SmallCaliberCentral

Hello I am not new to reloading, However ,doI need to use a factory crimp die when reloading for the Ar 15 in 204? This is my first 204 and ar 15 so I guess Im a virgin. I have around ten thousand cci 450 primers and both win 748 and Imr 4895 been very consistent powders in my 308 and 22-250. Just wondering if crimp is a must in a ar format?

I've had better luck with no crimp in my AR. Just make sure you have enough neck tension otherwise you will have big problems. I would use no less than .002 neck tension but probably would not go any more than .003 which may be a little much..........at least this has been my experience. I've had good luck with 27.8 H4895 with Rem 7.5 primers. My neck tension is .0025. and I'm seating at 2.255 using 39 gr Sierra Blitzking and i've got half in group or less at 100yrds.

How do you measure neck tension?

I use a crimp on my 223 only when the bullets are canaluvered?(??sp) for it. I have not seen any 204 made that. Just mentioning it.

I just my seating die per instruction for my 204. I don't know how to measure the tension.

To accurately know, you need either an inside ball mike, or use the tips on a vernier caliper, but burrs can cause inaccuracy. The hole diameter size is removed from the true bullet diameter, to tell neck tension.


I use a starrett split ball mike, then measure the diameter after fitting it snug- fit in the case mouth.


Hope this makes sense.

Remember, the .003 above is pretty large for a .204 diameter bullet, probably more likely for 35 and larger diameters, from my experience, although big bullets have more surface area, so maybe the .003 is better for small bullets? BTW I am now using one of the VLD inside neck debur tools and it is much nicer.

Allen

I think I get it although I have no way to measure it.

You can get an idea about neck tension by using calipers to measure the neck of a loaded round and then measuring at the exact same point on a neck sized round before a bullet is seated. Not the most accurate way in the world, but it will give you an idea. Fore example for a .204..........measures .228 loaded and a sized case measures .225 then I would have roughly .003 neck tension. If your using this method you need to be using the same batch of brass to be consistant.

Thank you, I definitely get that.

yes thx ryutzy
...that made some sense to me as well

Don't know how they'll shoot, but I hate H335 and love H322 every time I start testing...

I loaded imr 4895 and also 10x Both powders though different did very very well. I started with 4895 as I use it in my 308 and 22-250. The a trip to my local shop revealed 10x is very good in the 20s. Conclusion he was correct!

My method for measuring neck tension is pretty much 'seat of the pants'... When I'm seating the bullet, I can feel those rounds where the bullet slides too easily into the case and I will pull the bullet and pull the decapping pin and resize the case...almost always it tightens up the neck and I've never had a known problem with the bullet sliding back in the case while shooting..

Whether this has to do with the amount of lubricant on the case neck (inside or out), I have no idea as I'm using a Forster Co-Ax press and Forster Benchrest dies, that have always produced accurate rounds... My brass is always prepped the same way, in the same runs of reloading...I know it's not scientific or really precise, but so far it works for me..

I have shot over a hundred and fifty rounds now through the ar. I am like you it seemed as the bullets were seating plenty snug. So far they have all fired accurate and consistent. I have no broblems with bullets being to loose. I just didnt know if crimp was needed, and it isnt. Thanks