Magazine Feed Box Length vs. COAL – How to Maximize?

[Full Curl]

As a general rule of thumb so to speak (if there even is one), what do you really experienced hand loaders use to determine maximum COAL of a cartridge in order to ensure it correctly feeds from a rem 700 short/long action BDL magazine? I can look up COAL in a manual but I want to measure the inside length of my magazine feed box and go back from there to determine my maximum COAL. In other words, I want to know how far back I should go from this inside length measurement while still being able to maximize my COAL?

Does caliber (case dimensions) come into play at all?

Thanks!

 

[Zen Archery]

Pre-Hammer bullet days when I worried about COAL I would load a dummy round and keep seating it deeper until it fit .010 off the magazine face.

 

[Carlos88]

As a general rule of thumb so to speak (if there even is one), what do you really experienced hand loaders use to determine maximum COAL of a cartridge in order to ensure it correctly feeds from a rem 700 short/long action BDL magazine? I can look up COAL in a manual but I want to measure the inside length of my magazine feed box and go back from there to determine my maximum COAL. In other words, I want to know how far back I should go from this inside length measurement while still being able to maximize my COAL?

Does caliber (case dimensions) come into play at all?

Thanks!

If it fits in the magazine properly it should feed like any factory load. Chase straight ammunition first. If your runout is bad the OAL won't matter much.

 

[Shane Lindsey]

What Ed said!

 

[PddPdd]

I agree with checking how your ammunition feeds in your weapon. Make it as long as you want providing it feeds reliably.

 

[misterc01]

Yup -What Ed, Shane and PddPdd said....................

 

[jrock]

My rule of thumb is to leave 50th+ of space in the mag. I have some light recoiling guns with long throats that I just seat the bullet to barely fit in the mag and go have fun. I've had larger recoiling guns smash nose tips in the mag. Some care should be taking in determining a COAL to mag fitup.

 

[judgebill]

This is only by way of a suggestion. If your hunting experience has been successful with only one shot (i.e., the animal was anchored if not killed outright with the first shot), then you have plenty of time for the second shot. Which means the COAL isn't important when deciding how long the cartridge can be. Load each round by hand. This avoids inertia damage to the tips of the bullets when inside the magazine. Measure COAL for accuracy, not for the length of the magazine.

 

[Full Curl]

Thanks for the replies. I've read different advice but most put it somewhere in that 0.01" to 0.06" range. I primarily only shoot tipped bullets so maybe there's less risk to tip damage than there would be in a soft lead nosed bullet?? I'm so used to shooting at the range loading 1 at a time, I sometimes forget about COAL and mag length for hunting. I'm getting pretty close to mag length in one of my rigs that has a lot of rounds down the tube with decent throat wear trying to stay 0.02 off the lands. I have extended mag boxes in a couple of my other rigs so I'm hoping those won't ever be an issue and I'll need a new barrel before worrying about COAL. I do shoot a couple short mags and to me they have always not fed as consistently and smoothly as a regular mag case. I'm thinking the longer the COAL in these, the more possible issues I may have?? I get so use to slowly cycling the bolt at the range to grab the fired case when shooting before it goes flying, that I will even sometimes do this when hunting rather than quickly dechambering and chambering in another round quickly with some force. The slower I cycle a bolt action the more risk to feeding problems I feel 'll probably have.

I think I'll fully load the magazine up in my 300rum and see what happens to the bullet tips with I touch that one off. I'm assuming it's best to have the head of the case rest against the rear face of the mag box or should they be pushed a little forward when in the magazine?

 

[RegionRat]

I get so use to slowly cycling the bolt at the range to grab the fired case when shooting before it goes flying, that I will even sometimes do this when hunting rather than quickly dechambering and chambering in another round quickly with some force. The slower I cycle a bolt action the more risk to feeding problems I feel 'll probably have.

It is easy to burn in a training error when we practice the wrong way or shoot off a bench differently than when under stress in action.

There comes a time to practice away from the bench using field positions exactly like where you will hunt. When you are practicing on those days, be sure to cycle the bolt like you mean it and don't go back to bench shooting habits till the next time you find yourself needing load work.

If the rig jams under those circumstances, Murphy's Law says it will also jam when you are hunting too. Get it sorted out and don't press your luck.

There is usually an opportunity to go back and collect brass, but sometimes there is not. A small price to pay to the gods of the mountain for the kill.

 

[FEENIX]

As a general rule of thumb so to speak (if there even is one), what do you really experienced hand loaders use to determine maximum COAL of a cartridge in order to ensure it correctly feeds from a rem 700 short/long action BDL magazine? I can look up COAL in a manual but I want to measure the inside length of my magazine feed box and go back from there to determine my maximum COAL. In other words, I want to know how far back I should go from this inside length measurement while still being able to maximize my COAL?

Does caliber (case dimensions) come into play at all?

Thanks!

"I" find the best compromise between COAL/CBTO/seating depth without any feeding issues and still have the accuracy required for the intended purpose.

 

[Shane Lindsey]

Depending on your barrel life and the bullets you intend to shoot it may be worth considering getting some work done. At least on the RUM.

I have had the mag well opened up to accept a Wyatt's mag box on a 300 RUM and a 308 win. The RUM functions fine, but the 308 still needs to have the feed ramp adjusted to work with the long loads.

 

[FEENIX]

Depending on your barrel life and the bullets you intend to shoot it may be worth considering getting some work done. At least on the RUM.

I have had the mag well opened up to accept a Wyatt's mag box on a 300 RUM and a 308 win. The RUM functions fine, but the 308 still needs to have the feed ramp adjusted to work with the long loads.

Yep! The RUM requires longer COAL/mag clearance (close to the 4.00" range) to take advantage of the long/high BC bullets. One of the reasons I went with the Norma over Lapua on my current build.