There is a tab on the loading gate that helps hold the rounds forward in the magazine, but in the Henry/66/73 design, the magazine stop is also the cartridge in the carrier, so overall cartridge length is critical. In a 44-40 bullet, the crimp groove is always in the correct place, but there are so many possible bullets for the 38Special that it's hard to know which one is right. You need to determine the correct overall length for the 38 Special in that rifle. Check the loading gate to see if the ammo is getting past it when the carrier is up.
