Why no last round hold open

[PolishX]

I was told that mp5's don't have a last round hold open . Is this true ? And why not I'm curious

[bluetwister]

That was a problem in selling the 91's and more importantly trying to compete with the AR's with a 93. What I was told by more than one engineer from Oberndorff, was that in a combat environment, the open bolt would allow debris and foreign matter into the weapon and this was to be avoided at all costs. More recent models of the MP5 and some of the "sniper" rifles do sport bolt hold open devices, but I believe that they started as special order for the US government, and were held over in regular production. G3Kurz might lend a bit of info on the subject.

[Marine0303]

The Bolt Hold Open or BHO was not introduced on the MP5 until the MP5-40 and MP5-10, as part of a "user-inspired" improvement to the MP5 platform. Officially, it was at the request of the FBI, who were the reason behind the development of the MP5-10.

[BlackScorpion]

I would really like to have it on my MP5 also. But everything I have seen it is only an option for the .40/10 models. And like was already stated, it was only at the request of the FBI that those models have it.

[Chopstix Kid]

I have a 9mm BHO in progress for a member here. Been working on it slowly over the last year along with a D54P/45 that takes UMP mags. Stay tuned.

[PolishX]

No worries , just was curious because I'm sure when I shoot it someone will ask why it didn't . And I want to sound smart and have a response when they ask me

[Chopstix Kid]

Sorry, I never added to answering the question...

In Europe, many arms do not have BHO which is indicative of how they train to use firearms. They are taught to count rounds fired and to change mags before the gun runs dry. While a valuable skill, it counters what HK-D recommends for the MP5/9 which is to always open the action before inserting mags. Again, difference in U.S. and European training.

[Shattered Mind]

No worries , just was curious because I'm sure when I shoot it someone will ask why it didn't . And I want to sound smart and have a response when they ask me

Just tell them that HK hates us and thinks we all suck.

[PolishX]

Perfect I'll just say " it's european" it's exactly what I say when people ask why I paid so much for my watch LOL

[G3Kurz]

That was a problem in selling the 91's and more importantly trying to compete with the AR's with a 93. What I was told by more than one engineer from Oberndorff, was that in a combat environment, the open bolt would allow debris and foreign matter into the weapon and this was to be avoided at all costs. More recent models of the MP5 and some of the "sniper" rifles do sport bolt hold open devices, but I believe that they started as special order for the US government, and were held over in regular production. G3Kurz might lend a bit of info on the subject.

Bluetwister is correct. Marine is close.

The first bolt hold-open (bolt catches) were not used in the MP5/10 and MP5/40 but that was inspired by the FBI involvement in the 10mm Auto MP5 on which I was the US PM at HK. It was a real trick to fit it all into a MP5 using existing tooling. The first version with the role pin were not reliable so a threaded screw was later added to new and retrofitted into already fielded guns. HK GmbH never wanted to make the MP5 in 10mm - said it would never sell. It did of course - 5000 to the FBI and 5000 .40 S&W MP5/40's to a wide selction of LE agencies.

The first HK production gun with a bolt catch was the 5.56mm G41 rifle. HK intended that weapon to compete with the M16 and thus gave it the same features to include the bolt catch. The prototype SMG, SMGII and MP2000 subguns also had bolt catches.

As Bluetwister stated it was added to improve weapon relaibility in harsh environments especally where sand and grit is airborne when your bolt is open - the the desert, around helos, etc. Adding ammo viewing holes in mags also reduces reliability in such environments as it allows sand and dust to get inside. It is also a cultural thing - if you don't grow up using one you make due without.

Also one important point is often overlooked. Watch/film someone under stress firing two rifles to empty - one a HK33 w/o bolt catch and an M16 or HK G41 with. Note what tells the shooter the gun is empty. It IS NOT the bolt locking to the rear but the lack of a response from the weapon when the shooter pulls the trigger 1, 2 and 3 or more times THEN they look up to see the open ejection port. If you are concentrating on engaging the target you aren't paying attn to the function of the bolt catch. Therefore an argument has been made that the only advantage of a bolt catch is that it speeds reloading because you do not have to actuate the cocking lever which is slower than hitting the bolt lock release and that is true but it is not really the indicator during firing that you are empty (unless you are paying attn to that and not concentrating on hitting your target) - the trigger finger pulling the "dead" trigger is.

HK resisted bolt catches on their weapons for many times until they finally gave up and under Ernst Mauch added them because the customers demanded them. Ironically bolt catches came out on all new HK weapons as HK migrated away from roller locking and sheet metal receivers.

G3Kurz