Where is the clear length measured?

A: Between the furthest support faces inside the cavity, never on the outside. Walls, ribs and corner guards add 30 to 50 mm, so a case bought on its outer length leaves the item pressing the end wall, with no crush travel left at either end.

Why are two end supports not enough?

A: Two blocks leave a free span that lets vibration work the foam until the slot widens and the item slides. A long weapon case spaces blocks at a third of the item length, capped at 350 mm, all at equal density so no hard point gathers load.

May the end allowance be packed solid?

A: No. Packed solid it has no travel, so impact passes straight to the end wall and no guard can help. Leave 20 to 30 mm of closed-cell polyethylene below the density of the locating foam, so it crushes first and the foam behind it stays intact.

How is the handle position set?

A: Put its axis through the loaded centre of gravity. Shift that centre by a tenth of the length and the case noses down, loading the wrist. Strap loops sit in pairs within 150 mm of it, and on a long weapon case the wheel track runs at least 60 percent of the width. ---

What a Long Weapon Case Is: Cavity Length, Support and Carry

Quick answer: Ask where the length is measured: a long weapon case is a rotomolded shell whose outside comes from one inside figure, the clear cavity length. That length splits into a cradle, a support run and an end allowance that also acts as crush travel. Blocks sit no more than 350 mm apart, ends keep 20 to 30 mm, and the carry method follows loaded weight and balance. Each zone has one dimension worth writing down.

Definition: clear length first, outline second
Cavity: three length zones and end travel
Supports and latches: splitting the impact path
Carrying: handle, straps, wheels and balance
Acceptance: four numbers decide the delivery
FAQ

1. Definition: clear length first, outline second

A long weapon case is a rotomolded shell whose outline is derived from one inside figure: the clear cavity length. The distance between the two end support faces is drawn first, then width, height and wall thickness, because the outer length includes both.

Open case showing twin-wall edge and draw latches

So the clear length needs its own row, with its datum named. Quote the outer figure alone and the risk moves to the user. In a long weapon case, add 10 mm of handling clearance at each end before the mould is cut.

Zone	Job	Share of length	If it is wrong
Cradle	wraps the fixed end	about 20 percent	the end rocks in its slot
Support run	continuous support along the length	about 70 percent	the middle sags between blocks
Allowance	absorbs tolerance and crush travel	about 10 percent	the item presses on the end wall

2. Cavity: three length zones and end travel

Inside, the cavity splits into a cradle, a continuous support run and a far allowance. The cradle wraps at least a third of the outline with a 2 mm chamfer, since square edges crumble first; the allowance runs 20 to 30 mm and works as crush travel.

U-shaped cradle and support blocks along the cavity

Never pack that allowance solid, or travel drops to zero and impact reaches the end wall. A long weapon case uses closed-cell polyethylene below the density of the locating foam, so the end crushes first and the foam behind it stays intact.

3. Supports and latches: splitting the impact path

Damage in a long item starts where it spans unsupported. With 300 mm of free span, vibration works the foam until the slot widens and the item slides. In a long weapon case, blocks sit at a third of the item length, never beyond 350 mm, all at one density.

Three draw latches and a corner guard along the long side

Latches cover the lid span. Past 400 mm without one, the lid breathes and the gasket opens. A long weapon case takes three latches to 900 mm and four at 1200, keeping guards and latches on separate load paths.

4. Carrying: handle, straps, wheels and balance

Weight and balance pick the carry method. The moulded handle sits on the centre line, its axis through the loaded centre of gravity; shift that centre by a tenth of the length and a long weapon case noses down in one hand.

Long case strapped to a vehicle cargo floor

Wheels go under the end face at least 60 percent of the width apart, or the case tips when pushed sideways. Treat 18 kg as the one-hand ceiling and move to two people or wheels above it; moulded feet 15 mm high keep the base off wet floors.

5. Acceptance: four numbers decide the delivery

Acceptance measures four things: clear length, support spacing, end travel and loaded balance. A tape and a flat pad are enough. Check length between the furthest support faces and query the drawing beyond 3 mm of error.

Work in order. A short cavity cannot be rescued by any liner, poor spacing loses location however exact the length, and a long weapon case that ignores weight cannot be lifted. Put those steps on the goods-in form, where numbers survive.

Conclusion

Judge a long weapon case in three moves: clear length, supports, carry. Confirm the length is taken between support faces with the allowance intact, check block spacing against the ceiling, then match loaded weight to the handle axis. All three are tape checks at goods-in and all three can still move on the drawing. Length is the one figure no liner can fix once the mould is cut.

This article covers container-side specifications and design implications only, not the handling, loading or use of the contents.