how hot did a MG42 barrel get

A MG42 barrel could get over 300 F / about 150 C if fired hard and fast, and it could become bright red-hot under sustained bursts. Sources also note the gun was designed for very short firing cycles, with barrel changes often needed after roughly 150 to 250 rounds of rapid fire.

What that means

• 300 F / 150 C is a commonly cited lower bound for an overheated barrel.

• In very intense firing, the barrel could glow red, which implies temperatures high enough to visibly radiate heat.

• The MG42’s very high rate of fire made heat buildup happen extremely quickly, which is why barrel swaps were part of normal operation.

Practical takeaway

If you’re looking for the simple answer: it got hot enough to warp, wear out quickly, and sometimes glow red during sustained fire. That’s why crews carried spare barrels and changed them often.