Seat to mid-cannelure?

[tcoz]

I'm currently loading 55gr X-Treme FMJBT over 24.2gr of H335 for my AR. My question involves seating depth. Cases are trimmed to 1.750 and I've been seating to a COL of 2.250. Accuracy is very good (for me) and the gun functions flawlessly, but the bullets are only seated to the very bottom of the cannelure, barely touching it, at 2.250. Changing seating depth to 2.20 would bring it more into line with the mid-cannelure rule of thumb but I hate to mess with anything at this point. Is there any reason I should do this or should I just leave well enough alone? Since bullets come both as cannelured and non, I'm hoping it's just there as a guide. BTW, I use mixed brass and CCI41 MilSpec primers.

 

[cfullgraf]

Unless you are crimping your rounds, no need to worry about where the cannelure in the bullet ends up.

If it shoots good, who cares.

If you where crimping, and some folks prefer to crimp their 223 Remington ammunition, you would get a better crimp if the case mouth was more centered in the cannelure groove.

I do not crimp any of my ammunition loaded for semi-automatic rifles such as the AR-15

 

[tcoz]

Thanks. I was hoping that's what I would hear. Actually, I am crimping, but only very very light crimp using FCD. I measured my crimp as only .001, which seems to me I'm probably only doing it so I can tell myself I'm using the die. I use a 4-hole LCT press and if I find a better use for the fourth hole, I'll probably just remove the FCD.

 

[FROGO207]

FWIW I tried both crimp and not and found for me that no crimp on 223/5.56 was more accurate. As long as the bullet does not move that means you have good neck tension and all is good. I also feel that the necks last longer if not crimped as they are worked less. YMMV

 

[tcoz]

FWIW I tried both crimp and not and found for me that no crimp on 223/5.56 was more accurate. As long as the bullet does not move that means you have good neck tension and all is good. I also feel that the necks last longer if not crimped as they are worked less. YMMV

Would a crimp of .001 be considered no crimp?

 

[Walkalong]

Pretty much.

I seat 55 Gr FMJ bullets to the cannelure because they were designed to fit the mag and feed seated to that length.

Not that you could call the marks on the X-Treme 55 Gr FMJ a cannelure, just a reference point. I give them a hair of a taper crimp as well, to ensure the case mouth is nice and flush. I also chamfer and deburr the case mouth before loading.

So no, I am not really crimping them, just making sure everything is smooth at the case mouth.

 

[tcoz]

Pretty much.

I seat 55 Gr FMJ bullets to the cannelure because they were designed to fit the mag and feed seated to that length.

Not that you could call the marks on the X-Treme 55 Gr FMJ a cannelure, just a reference point. I give them a hair of a taper crimp as well, to ensure the case mouth is nice and flush. I also chamfer and deburr the case mouth before loading.

So no, I am not really crimping them, just making sure everything is smooth at the case mouth.

A reference point is exactly what the "cannelure" on the X-Treme bullets looks like. I've seen cannelures on bullets before and they're deeper and more distict. They appear to be more "precision" than the ones on X-Treme builders.

I only chamfer and deburr on cases that I've trimmed. If I don't have to trim them, I don't chamfer and deburr. That's acceptable, isn't it?

 

[gamestalker]

If it's not a FA AR, there is no need to crimp, thus no need to worry about where the canelure is located in relation to the case mouth. Just seat em to where you like em, and shootzem Lizabeth, as RC would say.

GS

 

[trigga]

i'm using the same bullets and trim length, i seated them at 2.20 with light crimp.

 

[ArchAngelCD]

Pretty much.

I seat 55 Gr FMJ bullets to the cannelure because they were designed to fit the mag and feed seated to that length.

Not that you could call the marks on the X-Treme 55 Gr FMJ a cannelure, just a reference point. I give them a hair of a taper crimp as well, to ensure the case mouth is nice and flush. I also chamfer and deburr the case mouth before loading.

So no, I am not really crimping them, just making sure everything is smooth at the case mouth.

I'm not using the same bullet but my process is pretty much the same. I'm using a Lee FCD to apply just a touch of crimp, nothing more.

 

[cfullgraf]

I only chamfer and deburr on cases that I've trimmed. If I don't have to trim them, I don't chamfer and deburr. That's acceptable, isn't it?

Chamfer and deburring is pretty much a one time thing until the case is trimmed again.

Saying it another way, if the case was chamfered before and not trimmed, no need to chamfer it again unless it got trimmed.

If you chamfer new cases, regardless if they get trimmed or not, it will knock off the inside edge of the case mouth and make bullet seating a little easier.