Here is an image is of the an original prototype submitted by Browning and accepted as the 1927 Grand Rendement. Which later came to be known as the 1935 Grand Puisance. Looking at the gun that JMB finished you can see what we call the BHP but clearly it is not the same gun. The pic below is prior to Saive's re-work.
The original Grand Rendement has the double column 15+1 round mag but does not have a mag disconnect. The feature was later added by Saive at the because the French ordnance board requested it. Remember this was a contract gun just like the 1911. The spec of the contract dictated a lot of what when into the finished product for good or for bad.
Many people forget that there JMB originally submitted 2 designs... one of which was a striker fired gun....
and then this which I think is 70% to 75% of what we call a Browning Hi Power.
Here is a pretty interesting write up... http://forums.somethingawful.com/sho...readid=3310599