I have been shooting trap fro several years now and recently entered into a slump. I am trying to diagnosis my problem, I am currently using a modified choke. Should I be using a full choke instead? Thanks in advance for your help!

It’s very unlikely to be your choke. Check your eyes, gun fit, technique, timing many times over before you think it’s the load or choke.

Since you've been shooting for several years and at one time better - I like RB above wouldn't change chokes or loads.

Is your mount consistent?
Are you staying mounted through the entire shot (in other words, not lifting your head)?
Are you looking at the target? (I know this one sounds stupid but until you know how and when to look at the target and how much focus it actually takes NOT to look at anything else during the shot then you may be looking at the gap, at the barrel, or anything but the target).

If you think you've got the above 3 down, I've done the following in the past to get back to where I need to be.

Go to a club that will let you lock the trap on straight away and shoot the target at your regular cadence until you dust it a dozen or more times straight from post 3. If you need to do the same from 1 and 5 on hard left and right respectively, do that.

What have you tried to fix your slump?

Good suggestions above.
It could also be that you're shooting before clearly seeing the target.
I tell myself "wait' after mounting the gun and it has helped.

Are you shooting with 2 eyes open? ....Your eyes may be sporadically shifting dominance (also known as "cross-firing".)

When this occurs, your off-eye tells your brain the target is "there" while your gun is aligned with your other eye and shoots somewhere else.

Yes! If you want to learn how to center pattern every angle.

Keep notes on your form and mount. Make one change at a time to see if it works. Add discipline to your routine and shoot each target on purpose. Your issues leading to a slump will be easy to fix because they are usually rooted in your basics. Just need to be self analytical and consider each and every aspect of the shot delivered.

If you have had a recent weight gain or loss the gun fit changes.....POI changes. Having issues with eye dominance can cause many lost targets and hard to find a fix or reason. If it just lazy effortless shooting, what most call fun shooting. Put some purpose and discipline into the effort or get serious if not happy.

Buy a video to reference back, watch 'em for free on the computer. Actually learn what it takes to be a good shooter. Its much more than just putting lead down the barrel with your buddies. Some would call it work.

Maltz

Something has changed, and it isn't your loads, your gun, your choke, or your targets.
The change lies with you.
Speaking of eyes, have you had your optometrist check yours lately??

Slumps. We all have them. Concentrate on the basics and on your focus/concentration.

M / M for now that way you can see your chips,which is better than missing

You might consider setting up a camera on a tripod behind you. Record what you are doing and you may find that you've picked up a bad habit.

Gamin GPS targeting radar system will answer all questions on where the shot was placed in relationship to the target. Many clubs have one available or have someone with one available. You still need to find out why your not center target, but you know exactly where the shot was deliver on every angle, height and speed. For shooters that have learned the old fashion way, (full choke - reading targets) we can call most shots, but not as accurate as the GPS. It is the best training tool in existence. Instant results every shot.

How much is that worth? maybe a thousand.

Maltz

I think your probably trying too hard and not just shooting targets.
put your focus back where it belongs and stay loose.

The only problem I see with the Garmin (not "Gamin) is that it only tells you where you missed, not why you missed.
You need an experienced person watching you to catch any little nuances in your form/procedure that might be causing you to drop targets. Beyond that, it's going to be in your head.

Full choke.

Many thanks to all who took the time to answer my question. Your suggestions were most helpful!

Coincidentally I am reading Dr. A. C. Jones’s book, “Sporting Shotgun Performance” right now which I recommend to all of you. And I just finished the section in which Dr. Jones shows plots of the probability of hitting a target as a function of pattern spread (the diameter of the circle which contains 75% of the pellet load) and shooter accuracy (diameter of the likely circle a shooter will hit centered on the point of aim on a scale from 0-50 inches). He uses pattern spread instead of pattern efficiency, the % of the pellet load which hits inside a fixed 30” circle. Long story short, it is abundantly clear that shooter accuracy is far more important than choke constriction over a pretty significant range like best voice of choke +/- one constriction. So, for example, in Trap, mod, improved mod or full would be hardly different. But going from 0-30 inches for the accuracy circle at any of these constrictions is huge.

This book isn’t an easy read, but it is so worthwhile.

I should also mention that Dr. Jones concludes from the studies I mentioned above that more accurate shooters profit slightly from using somewhat tighter chokes while less accurate shooters have a slightly higher probability of hitting the target with somewhat less constriction. I suspect that is what we already intuitively knew, but it is reassuring to see it demonstrated empirically.

I also have Dr. Jones' book and when repeating his beliefs on TS.com about chokes for trap, the moderator promptly banned me. Probably permanently.

I don’t see the source of friction. Do you know what the supposed crime was?

You already know the answer.......there’s no rhyme or reason there.