Reloading - when your mag box limits your COAL

FEENIX · Sep 22, 2024

memtb said:
Another reason for a mono, especially in a heavy recoil rifle. Before I changed to mono's, by the time I got to the last round in the magazine……the bullet tips were so badly "flattened", I expected to see that the jacket had started to open! memtb

Are you saying a .001" of clearance is OK with monos? Monos or not, I always allow enough clearance. Also, I don't particularly appreciate touching the land. I have all kinds of monos, but C&Cs are my preferred bullets.

Below is a 117 Cayuga in my .257 WBY. .020" off the lands and .178" mag clearance.

Below is 145 Black Hole, also in .257 WBY. .020" off the lands and .189" mag clearance.

Another one with 163 Chinchaga, .015" off the lands, and .170" mag clearance.

memtb · Sep 22, 2024

FEENIX said:
Are you saying a .001" of clearance is OK with monos? Monos or not, I always allow enough clearance. Also, I don't particularly appreciate touching the land. I have all kinds of monos, but C&Cs are my preferred bullets.

Below is a 117 Cayuga in my .257 WBY. .020" off the lands and .178" mag clearance.

View attachment 603971

Below is 145 Black Hole, also in .257 WBY. .020" off the lands and .189" mag clearance.

View attachment 603972

Another one with 163 Chinchaga, .015" off the lands, and .170" mag clearance.

View attachment 603978

No Sir! I'm on two different forums, and this is an active topic on both.

On the other forum I stated, "I do not measure…..but, cycle a magazine through several times to be certain of function"!

I apologize for "my" confusion…..as I thought that I had posted the above comment on this forum!

My comment about the mono's was supposed to be an addendum to the above comment. A comment on another forum!

That's "clear as mud" to me, probably confused myself……I hope that this made some sense to you! memtb

Tiny Tim · Sep 22, 2024

When I've run into this issue, I generally like .030" or more shorter than mag length for Magnum cartridges. This seems to be fairly forgiving in terms of feeding and nose damage. I'm running .090 off to get in a Savage 300WM factory mag using 210 HVLD, and they group around .625MOA.

As YZ-80 pointed out. AR mags with polymer tips seem to allow for less clearance.

My 300 RUM is at 3.966 COAL in a 4" Wyatt's box for .015 off the lands and feeds well.

std7mag · Sep 22, 2024

I only have 2 rifles that the magazine is shorter than the cartridge base to lands length.

I'm like @FEENIX in that I leave 0.03" COAL shorter than internal magazine length.

med358-boise · Sep 22, 2024

Thanks guys for all the thoughtful replies

Ol' Red · Sep 22, 2024

memtb said:
never said I shooting at game……merely shooting! Eliminating lead tips will also change the equation! memtb

Once. And there was a witness.

I misjudged distance and angle badly.

K.E.C. Darkside · Sep 22, 2024

I don't like to be any closer than 10thou and sometimes 20. Depends on feeding.

Hoss50 · Sep 22, 2024

My 300wm is limited to 3.60" OAL. I load them to about 3.57"

BrentM · Sep 23, 2024

med358-boise said:
What amount of clearance do you use for your cartridge COAL? In other words, regardless of your desired distance to the lands; you always allow a minimum of X thousands under mag box length?

As long as it feeds the rounds through the mag I call it good. Usually that is a few thou under the internal max

VLD Pilot · Sep 23, 2024

med358-boise said:
Let me try to be clearer in what I am asking - Regardless of desired bullet jump, sometimes mag boxes are a limiting factor, so for those times when mag box is a limiting factor, do you have a minimum clearance for the mag box that use for reliability.

I suspect if someone's mag box was 2.900 inches and distance to the lands dictated a desired COAL of say 2.950 they would not load to 2.899 inches because only .001 clearance is probably a bad idea in a hunting rifle.

I realized that the Accurate mags without binder plates would allow me to load a 2.990 OAL 284 win cartridge to feed reliably. It was at that time that RL17 became fairly popular for the 284s shooting 180s and getting 3000 fps in LA rifles with 30" barrels. My target number was 3K. I wanted a SA 284 so decided to run my rounds at 2.980" and had a barrel chambered with the correct leade/freebore for that action and cartridge OAL for Hornady 162 ELDM bullets. I'm getting 3000fps with the 162s in a Short Action and 25" barrel with 2.980" loaded ammunition. Everything worked out for me with that rifle and it's a great hunting rifle that feeds flawlessly. I built it on a Rem 700 action, Bartlein 5R barrel and Manners stock.

Jeffpatton00 · Sep 23, 2024

I'd like to expand on this question - if I get the best results loading with CBTO of .020" off the lands, but the mag (with .003" clearance) requires a COAL that puts the CBTO more than that off the lands, does anyone know of an AR mag that is somehow engineered in a way that would allow loading closer to the desired CBTO?

Hugnot · Sep 23, 2024

Here is a pic of my .20P on a Ruger M77 MKII, once a .223 Rem, that that has a modified mag box to extend cartridge COAL by .1 inch. Perfect control feeding.

I use .243/.308 length Ruger mag boxes for my 75 ELDM .22-.250 loads.

FEENIX · Sep 23, 2024

Jeffpatton00 said:
I'd like to expand on this question - if I get the best results loading with CBTO of .020" off the lands, but the mag (with .003" clearance) requires a COAL that puts the CBTO more than that off the lands, does anyone know of an AR mag that is somehow engineered in a way that would allow loading closer to the desired CBTO?

You might consider starting a separate thread specific to your issue/concern. I do know exactly what chambering you have that utilizes an AR mag, but yes, there are mags that are modified to accommodate loads longer than standard mag lengths.

For instance, Cavity Back Bullets have a modified 10-round PRI modified mags for longer projectiles in 6.6 SPC, .224 Valkyrie, .22 Nosler, 6.5 Grendel, and 6MM ARC or wildcats based on the 6.8 SPC. Again, I am not sure of your actual chambering other than you use AR mag.

Here's a DIYer's video ...

mdmiller · Sep 23, 2024

Jeffpatton00 said:
I'd like to expand on this question - if I get the best results loading with CBTO of .020" off the lands, but the mag (with .003" clearance) requires a COAL that puts the CBTO more than that off the lands, does anyone know of an AR mag that is somehow engineered in a way that would allow loading closer to the desired CBTO?

Reloading - when your mag box limits your COAL

FEENIX

Well-Known Member

memtb

Well-Known Member

Tiny Tim

Well-Known Member

std7mag

Well-Known Member

med358-boise

Well-Known Member

Ol' Red

Well-Known Member

K.E.C. Darkside

Well-Known Member

Hoss50

Well-Known Member

BrentM

Well-Known Member

VLD Pilot

Well-Known Member

Jeffpatton00

Well-Known Member

Hugnot

Well-Known Member

FEENIX

Well-Known Member

mdmiller

Well-Known Member

Attachments

Similar threads

Recent Posts