Northants batting coach David Sales says his side could not have hoped for a better start at Gloucestershire.
The County have already claimed two of the four bonus points they need to make sure of promotion from Specsavers County Championship Division Two.
Rain brought an early end to day one, with Gloucestershire struggling on 80 for six.
Ben Sanderson has bagged two for 19, with Gareth Berg (1-8) and Doug Bracewell (1-17) adding to two run-outs.
And Sales said: "The day may have been cut short, but it has still been a very good one for us.
"We came into the game needing four points (for promotion) and we already have two of them.
"We're in a pretty good position all in all.
"To take six wickets before lunch is a really good return and we could not have asked for anything better than that.
"Ben Sanderson has been so consistent for a number of seasons now and he and Brett Hutton make a great opening partnership.
"They put the ball in the right areas and Ben was rewarded with a couple of wickets.
"There's not a great deal in the pitch, but he seems able to take wickets wherever and whenever this season.
"We've done a lot better with the bat this year and we know that, when the time comes, we will have to apply ourselves to get in.
"Once you get in, then it's a matter of building partnerships and making the opposition pay. That's something we've done well this season and we need to carry that on."
Northants started the day sitting second, five points ahead of Gloucestershire, who occupy the final promotion place.
And Gloucestershire all-rounder Ben Charlesworth said: "It's been difficult for us batting first at Bristol this season, but this is essentially a good wicket.
"It's not an 80 for six wicket and it's fair to say we haven't had a lot of luck.
"The two run outs were unfortunate and served to set us back.
"We're on the back foot, but there is still plenty of batting left and our first target has to be to try to pass 200.
"David Payne and Josh Shaw have scored runs on a regular basis this summer and there is no reason why we cannot get to a challenging total once the weather relents.
"The rain is frustrating, especially when you have one eye on what is happening in other games and cannot get out in the middle yourself.
"It's important we don't focus on what is going on at Durham to the detriment of our own performance.
"We know what we need in terms of points and we have to be very single-minded in that respect.
"We'll dust ourselves down and come back fighting."