This rifle has a "Rifle" length gas tube. The barrel is not threaded with a recessed muzzle crown. Mossberg should be able to answer the barrel diameter at the muzzle at Mossberg CS/product Information Tel: (203) 230-5300 | 8:00am-4:30pm Eastern

The barrel is not threaded and has a "rifle" length tube
The Mossberg MMR Hunter chambered in 5.56 NATO is perfect for just about any hunting outing that calls for a light and fast round. Not only is it great at putting meat on your table, but it also puts tiny groups of holes into paper targets like a target rifle too! The Mossberg rifle includes a Stark SE-1 pistol grip with integrated trigger guard, an A2 style fixed stock, an aluminum free float handguard with two sling swivel studs, an optics ready flat top upper receiver and a low profile 5 round magazine. The optics ready flat top receiver is perfect for mounting a high powered scope that allows you to really squeeze the last bit of precision out of this rifle. The 20" heavy profile barrel with a 1:9 twist is perfect for those lighter varmint loads that do a wonderful job of dropping game. Specifications and Features: Mossberg MMR Hunter semi auto rifle 29100 .223 Remington/5.56 NATO 20" Barrel Aluminum free float handguard Flat top upper Fixed A2 Buttstock Stark SE-1 pistol grip Dual front swivel studs Accepts standard AR-15 magazines 5 rounds Length: 39" Weight: 7 lbs Black finish

Its not threaded with a Rifle length gas tube

Hi Patrick Its not threVded, The Mossberg MMR Hunter chambered in 5.56 NATO is perfect for just about any hunting outing that calls for a light and fast round. Not only is it great at putting meat on your table, but it also puts tiny groups of holes into paper targets like a target rifle too! The Mossberg rifle includes a Stark SE-1 pistol grip with integrated trigger guard, an A2 style fixed stock, an aluminum free float handguard with two sling swivel studs, an optics ready flat top upper receiver and a low profile 5 round magazine.
The optics ready flat top receiver is perfect for mounting a high powered scope that allows you to really squeeze the last bit of precision out of this rifle. The 20" heavy profile barrel with a 1:9 twist is perfect for those lighter varmint loads that do a wonderful job of dropping game.
Specifications and Features:
Mossberg MMR Hunter semi auto rifle 29100
.223 Remington/5.56 NATO
20" Barrel
Aluminum free float handguard
Flat top upper
Fixed A2 Buttstock
Stark SE-1 pistol grip
Dual front swivel studs
Accepts standard AR-15 magazines
5 rounds
Length: 39"
Weight: 7 lbs
Black finish