MTM CASE-GARD Foam Insert for Ammunition Box FL-1-42

MTM CASE-GARD FL-1-42: The 1/2 inch thick, dark gray foam insert is used in the lid of compatible MTM ammo boxes. It dampens rattling during transport and keeps bullet tips away from the hard lid. This is a cut-to-fit padding – not an ammo holder and no additional locking mechanism.
Fits well – and when rather not

Fits well: if your MTM box has enough clearance in the lid, cartridges rattle audibly despite correct placement, and you want to neatly cut the insert to the specific box format.

Rather not fit: if the lid already fits tightly on cartridges or the insert, you want to fix loose ammo, or you are looking for a moisture-proof or shock-absorbing transport solution. The insert does not replace cartridge inserts, the bolt, or an approved transport container.

Which boxes can be padded with one insert?
According to MTM, one FL-1-42 is enough for the following cuts:

1 × R-100, R-100-MAG, RM-100 or RS-100
8 × J-20-XS
6 × J-20-M
5 × J-20-L or J-20-LLD
4 × J-20-MLD
halved for two regular 50-round boxes or one Deluxe-H50 box

The model list describes material yield, not a universal fit guarantee. Check the internal dimensions and lid clearance of your existing box before cutting.
Practical effect and limits
The soft lid padding reduces contact noise and can protect sensitive bullet tips from rubbing against the lid. However, it does not eliminate play in the cartridge insert. If the cut is too thick or too large, the lid may clamp cartridges or not close fully. Do not force the lock; instead, adjust fit and cut.
Black-Raptor classification: Useful as a small upgrade for specifically fitting MTM boxes when rattling and lid contact are the problem. For secure hold of loose cartridges or robust outer padding, a properly sized ammo box or suitable insert is the better purchase decision.
Cut and insert safely

Completely empty the box; remove ammo and ignition sources from the cutting area.
Measure the inner contour of the lid and mark it on the insert.
Cut away from your body on a cut-resistant surface with a suitable sharp tool.
Initially cut slightly larger and adjust fit step by step.
Insert the padding dry and close the lid without cartridges. Then check again with correctly inserted cartridges; nothing should be tightly clamped.

Keep the insert dry and clean, regularly check for deformation or decay, and keep away from oil, solvents, and aggressive cleaners. Replace damaged foam.
Scope of delivery
1 × MTM CASE-GARD foam insert FL-1-42, dark gray. Ammo boxes, cartridges, cutting tools, and fasteners are not included.