You won’t probably lose pounds (unless you diet) HOWEVER you will become stronger and *that* will allow you to do weight lifting after 3-4 weeks of working on a pilates reformer.
References :
http://www.pilates.com/html_files/resources/librarydocs/Intro-pilates-rehab.pdf

Now please do not get me wrong, I am not challenging you or your past – I just want to better understand why you have low stamina and strength. Is it a medical condition, just being overweight/obese? Lack of general fitness?

Always check with a doctor before you start a program – but that is the wonderful thing about any new routine or plan. It is your program – not someone else’s. The most I can offer you are tips and anecdotal experiences I have had based on my own trial and error as well as physical trainer endeavors.

1: Any activity, even low impact – is good activity. Frisbee, golf, biking, walking (leave running out if you have low stamina or are heavier as it can pound your joints hard) etc.
2: The duration you perform this exercise should not be based on a time, but your PE (perceived exertion). If walking at 2miles per hour is a hard task for you, then focus on improving that. Do some reading on aerobic levels and find what works best for you.
3: Learn about your heart rate – and your fitness zones. If you stay in the fat burning zone for your body type (mine is 142 +/- 5) for your heart – energy and endurance will increase. But if you build yourself a bit in the cardio zones, and start to train your heart (mine is 165-175) – endurance will increase significantly.
4: Muscles have endurance as well – and unless they are trained – it will be low. Start with very low weight, and high reps. Say for example with one bicep you can curl 25lbs, and do 8 reps. Do that with 17.5lbs and do 15 reps in 3 sets instead of 8. Train this way on your muscle groups for 1-2 weeks, and then slowly start to increase the weight and decrease the # per set. Within 3-4 weeks you will find significant gain in your strength and muscular endurance. Enjoy it and keep driving it. If you want mass – higher weight lower reps will do it, if you want tone and lean long muscles – stick to lower weight and more reps.

I hope this helped.
References :

http://www.loseweight.anonymite.com

Hope This Info Helps
Cheers
References :

Losing weight is never an easy thing, but you need some activities that are "cardiovascular". This means that you need to do some activities that will make your heart beat faster and make you sweat a little, too. Walking on the treadmill is great for that. You should do maybe 30 minutes a day if you can and you will see yourself begin to lose weight.

If you like to dance, run, walk outdoors, play tennis or something else like that, that would be a good substitute if you get bored with the treadmill. You can switch off and do a different activity on different days. Be sure to do something you like to do, though because it will help you keep interested in your goal longer.

Weights and squats are good for muscle strength which is also important in keeping strong healthy muscles and bones. Many people overlook this part. Try to do at least 10 minutes of this each day or 20 minutes every other day.

Don’t skip meals even though you may be tempted to. This will mess your body up and it will "fight" to retain your extra weight if it begins to think it is being starved. This is called "resistance" and it can be an awful thing to overcome when trying to lose weight. Losing weight this way will only slow down the process and when you do lose weight you won’t be able to keep it off.

Add more fruit and veggies to your diet and cut out the soda pop, juice, candy, other sweets and anything fried. I know this is really, really hard. You should have some of that stuff once in a little while, but try to get that yummy-yucky stuff out of your diet while trying to lose weight.

I don’t know that shooting (do you mean skeet or clay shots?) is really an exercise or that it will contribute to your goal.

Good luck and remember to do things you like!
References :