I'm very new to reloading and just got setup to get started and couldn't stand it any longer so I gave it a try today and it didn't exactly go how I would've liked it to. Before I got interested in getting into reloading I was buying reloads from a friend and every round he loaded for me chambered and shot flawlessly. When I set my die up today I took one of his rounds and used it as a gauge on how far to screw my die down and where to set up the seating stem and all went smooth. So I took some brass that I trimmed to the correct length deburred and chamfered. I first started off using hornady 7mm 139 btsp and they would chamber and eject but when I would lift the bolt and lock it down it was quite a bit more difficult than with the round I used as a gauge. I did this same thing with 5 different bullets and pieces of brass with the same results. I then tried it with an all new piece of brass and a 140 accubond which is the exact same thing as the the round I used as a gauge and hunt with. Even with this combo I got the same results as before so I stopped before I got really frustrated with it. Any help would be greatly appreciated because I don't have a clue what else to do. Don't know if it matters but the particular rifle I'm using is a remington 783 7mm mag.

Couple is questions/comments.
1. Did you trim before you resized or after?

2. You used his cartridge as a template however you have no idea where the brass really is unless you purchase the tools to properly measure in the areas that matter.

You didn't say if your brass was new or fired so my guess is it was once or twice fired brass and you did not bump the shoulder back or you trimmed before you resized then everything changed during the resizing.

3. Did you lube the inside of the necks before you resized?
4. Did you inside chamfer the opening before seating bullets or was it already chamfered? If you trimmed the brass you would need to chamfer again..

5. Did you measure the brass after you full length resized to see if it was within spec? If it was then you have a shoulder bump issue. You measure that with a bump gage.

To see if your brass was the same as his brass you need to measure brass oal and base to shoulder datum line using a bump gauge..

I trimmed,chamfered and deburred after fl resizing. The brass that I am using is once fired from my gun and some not. Yes I did lube the inside of the necks before resizing and I trimmed first then chamfered and deburred and measured it with my calipers which measured 2.489 and my manual said the brass should be 2.500.

Okay we are getting somewhere..
The only missing part is where the shoulder is.. you probably don't have bump gauges so can't measure that. This is the number one cause of a bolt being difficult to close.

7 mm is a belted magnum. I agree with everything pop_a_cap said AND would only add this= check around the belt. Measure with a caliper above the belt of UNFIRED new brass THEN measyre sized brass.

I completely missed the 7mm part.. that being the case it's headspacing off the belt. I don't load any belted cases but assume the shoulder being blown forward would still cause a hard bolt closure.

Something else I thought of.. possible you are seating your bullets a bit long. They could be hitting the lands before you get the bolt closed.

We still don't know enough about your issue except your brass oal is within spec. We don't know about shoulder measurement or how deep your seating your bullets.

If your buddy's brass chambers fine and your doesn't there is no doubt a difference somewhere and measuring those data points are the only way to find out exactly where the issue is.

Something else to concider with belted magnum = Cheap reloading dies. Friend had a OLD Lee die, he had same described problem. So I sized his brass with Redding S die problem solved. A cheaper die will sometimes cause a = bulge above the belt. We micd. it and it ONLY did it with the cheap Lee dies NOT the Redding OR the RCBS he bought latter. I also heard of a simpler case on Snipers Hide. Guy was using Hornady dies = Old ones not the new carbide dies. He had same problem as OP described.

Shooters, good info and only info you will learn from someone who's been doing this a long time... The OP will only know by measuring and comparing against known good brass.

I'm trying to emphasize to OP the importance of measuring the brass because that is the true method of knowing where you really are in the process.

I'm late to the party on this post, but back to square one.... make sure your shell holder is touching the base of the sizing die at full stoke and there is a slight cam over in the handle.

Trim.

Then chamber the empty brass and see what happens and report back.

I agree 100% . I would start with the most simple , measuring brass AND OAL or Ojive of bullet. Its always best, to save a piece of virgin brass for a reference. So what if you only load 99 rds. You will all ways have the Virgin brass to make measurements by.

Thanks for all the help I tried it again today with the same results but I did figure out that something is happening when I seat the bullet because I can trim,chamfer and debur the brass and it chambers just as smooth as can be but I can take and seat a bullet and not so smooth. After reading that it may have something to do with it being a belted magnum I decided to try it with a 243. I went through all the correct steps as far as I know setting my dies up and everything and just like with the 7mm mag all was good until I seated a bullet and in my 243 I almost couldn't even get the bolt to lock down at all so I'm not sure what's going on. To answer the question about the dies I'm using they're all RCBS either new or lightly used.

SOmething is not right 4 sure. Try this trim, chafer, and resize a 243 win. Since you have no bump gauges = then insert the just sized 243 win in to your rifle. IF IT close fine then your problem HAS to be in your seating die. IF YOUR seating die is not set up correctly, IT could be pushing the shoulder back. THIS could be WHY you are having chambering problems. Crimp could also be an issue IF your using a seating die WITH built in crimp.

If you have a factory .243 there assuming it chambers fine... measure that overall length and compare that to your handload.

If they are the same something is going on with seating the bullet in the case causing a buldge or crimp, etc. such as Shooters is saying.

If your slightly longer than the factory round and I'm talking a fraction, just seat the bullet a hair bit deeper. Sounds to me your bullet is just barely touching the lands if the bolt will close (but hard to close). DON'T FORCE IT. Getting one stuck in the chamber isn't going to be fun.

So all chambers are different. I have had several rifles where the book MAX OAL wouldn't chamber. When I get a new rifle in a new caliber I always have a couple factory loaded on hand. I do my sizing/triming/measuring. I'll chamber that empty sized/trimmed i.e. fully prepared case just to check the chamber and see if it is too tight, etc.

I throw that case in the box with the loading dies to measure off of in the future. Also write on the die box some of the specs and label with a sharpie "Trim" on that case.

Then I get another piece of brass and set up the seating die with an empty case. I may start a little longer than max just to see. Put it in the gun...Won't chamber... I bump it back a little (seat it deeper). Take it out and try and chamber again. Won't chamber? Repeat. Ok, 3rd or 15th time we are getting tight and bolt handle is starting to work. Bump a little more. I get that sucker right up in the lands where the bolt will still close but not stick or too hard. I label that case "Max OAL" with a sharpie and throw it in the box with the dies.

Here is where the load development starts...

Then I prime, and load 10 each with various grains of powder/ different powders.

Last important step...Then I adjust to die to bump it back just slightly so that the bullet is just off the lands. And I load some more. Who knows if a rifle is going to like that bullet right up in the lands or just barely touching or maybe just off.

And that is where the entire process of load development begins.

Either bullet not being seated deep enough or he's blowing shoulder out.. really not much left in the equation.

Curious to find out the culprit..

Thanks guys for all the help. When I get home from work today I'm gonna take one of my once fired 243 cases and fl resize, chamfer and debur. I'm then gonna see if it'll chamber in my rifle and let yall know how that goes but I have a feeling that I'm gonna have the same issue as I did with the 7mm brass because I think something is happening when I seat the bullet. It almost seems like the longer I seat the bullet it chambers just a little bit better but if I seat it deeper it's even more difficult.

Well I got home this afternoon and did what shooters told me to do as far as chambering a fully processed 243 brass. It chambered and the bolt operated just as smooth as could be so I took a bullet seated it a tiny bit at the time til I got just under max coal and just like all the times before the bolt was difficult to lock and release. I got to looking at my brass and noticed about a quater of an inch from the bottom on the side of the body of the brass there is a ring around all of my cases that I've fl resized and seated a bullet in and some of them are way more not icicle than others and on a couple I ran my fingernail over them and if feels kinds like it's slightly bulged out where the ring is.

So we know the problem is seating die. Im probably the wrong one to tell you HOW to adjust regular seating dies. I only use L E Wilson dies with an arbor press. I know, I know that not nessary for hunting rounds but as everyone knows I VERY OCD with my reloading. WHAT KIND of seating die are you using? DO YOU have it adjusted properly? CAN you post a pic of the way its seat-up? MY QUESS is that you have it= the seating die ran to far down. THis will often cause a bulge. IS IT caming over? HOw far from the shell plate is your die? What brand name die are you using?

I'm using a seating die that came with my RCBS FL die set. The way I set the die up is I run the shell holder all the way up as far as it'll go and I then screw my die down all the way until it's touching the shellholder. After that I back it off a quarter turn to where there's about just enough space to slide a sheet of paper between the die and the shellholder and once I have it where I think it needs to be I screw the lock ring down into place and tighten the set screw down tight. The next thing I do is back the seating stem off a little bit and seat the bullet a little bit at a time measing with calipers after each time until I get it to the correct c.o.a.l. All of my dies are fl die sets made by RCBS.

I think you are screwing the seating die down to far. Turn it back AT least 1 full turn or 2 . Then use the steam to run it down to seat your bullet. MY guess is you die has build in crimp and its crimping AS it seats the bullet. THIS may becausing it to BULGE you neck. Back it of a round or 2 and try it again