BMF: The Remington 30 action is a sporterized version of the P17 Enfield which was chambered in 30/06. Many P13 and P17 actions have been modified for the 416 Rigby and the 505 Gibbs because of the extended length of the action. The ideal width of the magazine box can be determined by rubber banding 3 505 Gibbs cartridges together stacking them as they would be in the magazine. Then measure the width across the rear of the cases and measure the width at the shoulder. This will give you the ideal width of the box and is obviously much wider than the same geometry of 3 30/06 cartridges. It is possible to to go narrower but you have to maintain the reduction the same at the shoulder as at the case head and you run the risk of the cartridges not feeding properly. At one time Gun Parts Corporation (the old Numerich Arms offered a magnum magazine box due to the popularity of the Enfield conversion. A-Square (no longer in business) also used the Enfield action for their Hannibel rifle.
Because of the large diameter of the 505 Gibbs case, the feed rails need to be opened up. I would check the dimensions of your modified action before investing any more money in your project. The rear of the magazine mortise should be 0.710" for 2.600" and than 0.650" to the end of the receiver opening. Gunmaker - The Journal of Custom Gunmaking issue 79 and 80 (pub. in 1997)covers this extensively.
A quote from Jim Wisener might be of interest to you: "I prefer 1914 303 bolts when going to the 505 Gibbs cartridge. The additional metal on the split lug leaves more material when opened up for the larger casehead. The 1917 bolts leave little very little metal at this point."
PM sent
It is physically impossible to make a magazine box fit the .505 Gibbs by "Mauser Cosine Law" and still be small enough to mate to the bottom of the rifle.
Such a magazine box does not exist.
No matter, whatever works, and surely Duane Wiebe can pull the needed tricks out of his bag.
Trapezoidal box wider at the bottom than at the top is one of those tricks.
Wiebe bank vault bottom metal used for 500 Jeffery on M98 Mauser:
Here is How CZ makes a sheetmetal .505 Gibbs box out of their ribbed .375 H&H box (from the "Sporting .408 Chey-Tac Part Deux" thread on Big Bore Forum):
HOW CZ-USA BUILDS A .505 GIBBS
First turn a CZ 550 Magnum .375 H&H box into a 3.950"-long .505 Gibbs box:
Cut off the front wall except for a small band near the bottom.
Weld in a box extension, inside the box to expand the box length.
Feed ramp now overhangs the front inside box wall a wee bit.
Place a 0.1"-thick rubber pad inside the front of the box, later ones were steel instead.
Box length is back down to about 3.85" with the bumper inserted inside front of box.
If instead, one trims about 0.050" off the rear edge of the feed ramp,
and then reinforces the front of the box outside, with a steel plate,
then magazine length is a functional 3.950" inside of the box:
Top front of box:
Bottom front of box:
Side of box:
Front of box:
Exquisite polishing of inside sidewall of box:
Top view of box:
Where the box goes:
Box inserted:
Adding a Wisner drop plate would relieve crowding a bit too ... not much, only about 1/10" depth added ... surely Duane Wiebe can do more than this.
I bought a Wisner "drop plate" and was shocked by how little depth it added over the standard CZ 550 Magnum floor plate,
which is afterall, also a bit of a pocket plate.
And lastly, why the simple rubber band trick won't work for the .505 Gibbs:
From the "404 Jeffery History" thread on Big Bore forum:
The cartridges stack into an equilateral triangle in cross section,
so the case head diameter determines how wide the box should be inside, at the back.
But tall skinny boxes can work just as well ... the extreme is a vertical single stack.
I have finally come to think naught of the "Mauser Cosine Law Perfect Box."
No such magazine has ever been made for the .505 Gibbs.
Make it that wide at the top and it will not fit on the action.
The CZ 550 Magnum box width at the rear is 1.052" (inside width).
This is greater than needed for the .404 Jeffery, however, my specimen (pictured above),
uses the same box width at rear, but ribbed box as used for the .375 H&H thus decreasing the effective width to perfection for the 404 Jeffery.
It is too large for the .375 H&H, and too small for the .416 Rigby, 500 Jeffery, and .505 Gibbs,
even when used without the ribs.
CZ uses the same box rear width for all of these cartridges.
The Winchester M70 in 404 Jeffery, pictured above uses the 300 RUM box which is a windowed box that is 0.975" in width at the rear.
This is how the "make-do" techniques work.
It seems to work well for the the 404 Jeffery.
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Some ideal box widths at the rear according to CIP maximums:
.375 H&H rim diameter of .5318" and belt diameter of .5339" maximum: box width at rear = 1.86603 x 0.5339" = 0.99627"
This is more than enough, since manufactured brass is always smaller than the CIP max.
404 Jeffery head diameter of .5429" maximum: box width at rear = 1.86603 x 0.5429" = 1.01307"
.416 Rigby rim diameter of .5902" maximum: box width at rear = 1.1013309"
500 Jeffery head diameter (rebated rim abomination, rim diameter 0.5751968") head diameter of .6188976" maximun:
box width at rear: 1.86603 x .6188976 = 1.1548814"
.505 Gibbs rim diameter of .6401574" maximum: box width at rear = 1.1945529" 
Forget about adding slop unless using the "rubber band method" to measure.
Using the max spec brass diameter will build in enough slop since the manufactured brass diameters are smaller than max spec anyway.
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Ryan Breeding used a rear box inside width of 1.09" on CHIPB's .505 Gibbs.
Ideal: .505 Gibbs rim diameter of .6401574" maximum: box width at rear = 1.1945529"
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quote:
Originally posted by DArcy_Echols_Co:
This might be a good time to jump into this thread. In regards to WORDS OF WISDOM from Burgess and magazine dimensions I can say without any doubt that arbitrarily adding +.015 or more to your width calculations is not what Tom ever told me. My statement is not made to kick sand in anyones face that may have posted before me. Tom's typical lectors can only be described as enigmas wrapped in controlled chaos.
Having spent many hundreds of agonizing hours on the phone with Tom or in his presence I can see why what Tom was addressing at any giving time could get a bit confusing. I have file folders filled with many, many hand written letters from Tom going back to 1980. Some I have never been able to completely decipher. When he typed a letter to you it was to make you very clear his ideas and thoughts. When he went to e-mail the cat was out of the bag and the readers learning curve went up if they paid attention.
In short Tom used the equilateral triangle method for Sakos, 98's, Mod-70's, Zkk's etc for the 222 Rem up to the 404 Jeffery diameter cases. The limiting factor at this point is the width of the actions underside. With an approximate rear ID Mag box width of 1.013 as an example for the 404 Jeffery the action side walls at the areas just above the rear end of the magazine starts getting pretty thin if your fitting a sheet steel Magazine box machined into the the recess of say a Mod-70.
When you get into the Rigby diameter cases and larger the rule that Tom used was to make a Rigby ID Box width about 1.032 or wider if he had to clean up the feed well in a wallowed out Mag Mauser or Brno. He would then duplicated the taper from the base of the case to the shoulder of the case. If the combined taper was .020 then he duplicated this taper forward on the INDIDE OF THE MAGAZINE BOX and the re-cut the feed well of the action to match the magazine box geometry. The few Gibbs he did ran about 1.060 for ID at the rear and the ran forward with the Gibbs case taper. I used this same specs for the 2 Gibbs I did recently. The followers were made accordingly to match the boxes. The larger the case diameter makes the LAW OF THE EQUILATERAL EQUATION become more problematic when you get into cases such as the Gibbs or 500 Jeffery. If you make the magazine as wide as you determine with your rubber bands or tape the position of the bullet nose is now placed further to the right and left of the centerline of the action, further from the bullet ramp and radically increases the angle of approach that the round now has to make as it clears and releases itself from under the rails, into the bolt face and up under the extractor. While this may seem minor I can assure you that the pin in now out of the grenade. I believe reference to the extra width was in fact made in error which I can sympathies with completely. I often thought the Navaho Code Talkers would even be befuddled in a conversation with Burgess.
However I do have have many of Toms written instructions on this subject and have used these instructions for 25 years. Many have said that he followed the "Mauser Formula" exactly but a close examination of his specs for the 375, 404 and the 416 Rigby etc will prove that they are not at all the same. Tom developed his own specs and followed them accordingly. I have stocked a lot of Burgess's barreled actions over the years and I have put the calipers to everyone of them and they all follow the same principal. I own a Magnum Mauser in my shop right now that was a 350 Rigby when it left London long before I was born. It made the rounds around the gun show circuit and eventually made its way to Tom's to be turned into a 416 Rigby. As a complete barreled action it is fit with one of his Magazines & followers, holds 4 down, 1 up and works flawlessly. The box is made as I described above, to a T.
There are many ways to get the same results. All are a variation on the same basic theme. Ralf Martini, Stephen Heilmann, Duane Weibe, Mark Penrod H&W, H&H, Max Ern, Prectl (you get the idea) may approach this procedure using different specs, widths and geometry . The bottom line is the end result, not how it got to there.
Morning all,thanks for the explanations and photos this has been a great help, I have now seen that from all the posts above, I will be able to use the existing box and floor plate, they need a slight bit of smoothing off and polishing but they will work just fine.I will have to replace the follower and the magazine spring though and thanks to Duane Wiebe, I will be able to use CZ follower and spring for this.If I am lucky I might also get away with getting the stock inlet refined and have it bedded properly.If this does not work, I will have to get another stock.
Those of you who have had a look at the muzzle brake, does this seem like a good idea, I am inclined to get it taken off and fit other sights? I do not know enough about muzzle brakes but I can say I have never come across one like this. Any idea from anyone if this muzzle brake is going to be effective or is it just going to make a lot of noise?
Take care!!!
quote:
Originally posted by BMF39:
Those of you who have had a look at the muzzle brake, does this seem like a good idea, I am inclined to get it taken off and fit other sights? I do not know enough about muzzle brakes but I can say I have never come across one like this. Any idea from anyone if this muzzle brake is going to be effective or is it just going to make a lot of noise?
Take care!!!
The muzzle brake:
Brazed on or screwed on and properly timed? Front sight on the brake is quaint.
Is there a minimum clearance at the muzzle exit hole that is no more than .040" in diameter greater than bullet diameter?
If so, the brake could be effective enough to be worthwhile.
Tighter is better where the bullet leaves the muzzle on a brake.
No doubt there are more effective brakes, and better front sight arrangements.
But something about that brake has worked sufficiently to save the stock from splitting,
and the front sight must surely be functional on an old warrior that has seen use in the past.
A make-over with screw-on brake and thread protector muzzleward of a banded-ramp front sight to match current sight height
would certainly add to versatility and function in recoil reduction and sighting.
quote:
Originally posted by BMF39:
Hi all, could not help myself today only received five very old rounds for the 505 and decided to go to the range and shoot them off. Rifle was amazingly comfortable to shoot and grouping was not bad at17yards but the sights are a little off to the left. Now for the rounds, first round i noticed that the primer was punched or either burnt the whole way through, second round was a complete miss fire,third round the case split ever so slightly on the shoulder,four round fine but the fifth round the primer had a burn hole on the edge and the case head looks like it either split or was arc cut as there is melted brass on the bolt face. I will send photos later. But for now any comments on why this happened. I really hope it is just because of old ammo and not a head space problem. Ther is absolutely no bulging or ring on the cases at all. A few very flat primers though.
I would suspect the ammo rather than the rifle for starters.
Some photos of the fired brass would be helpful.
"Old ammo": Was it handloaded/reloaded or factory?
Either way: If loads were not excessive when fresh, then tumbling them about in a bakkie box or ammo belt for many years
could degrade the powder to faster burn rate and cause excessive pressure.
Pierced primers and brass smearing that bad sounds like way over normal pressure.
Now you better have the rifle checked with headspace gauge to make sure no harm has been done to the rifle in the past.
Photos of the case head face and full length brass body and neck?
Just guessing here.
Your bolt face looks great, well made, except for the amazing amount of brass on it, which looks like a near disaster happened.
Better make sure the locking lugs have not been set back. Check headspace:
Here is the rough CZ 550 Magnum bolt face after 40 rounds of normal pressure .505 Gibbs handloads fired (good Jamison brass),
before any cleaning,
though I must say that it also got smeared by trying to chamber some defective A-Square-made .505 Gibbs ammo
(originally sold by CZ, but no more) that would not even chamber at all.
Even with all that, not nearly as much brass on this bolt face (.700" bolt body diameter):
Did your "old ammo" have defective brass?
Too soft? Annealed case heads?
Clean MRC M1999 PH .505 Gibbs bolt face for comparison (.805" bolt body diameter):
