I have just measured my Tikka 22-250 and made a dummy load taikng 30 thous of my mearurement(I am using a comparator set).I have neck sized my cases which have been once fired in my gun,but i find that the bolt seems "tight" on the final stage of driving the load home.i am getting no rifling marks on the bullet ,but according to my Nosler reloading manual the max overall length of my load should be 2.350(Some figure with strange letters next to it "s u m i" or something of that nature)but i have a overall length from tip to tail of 2.500 and my bullet is a Nosler 55 grain ballastic tip which is seated appx the width of the bullet into the case.I am new to reloading and i am a little worried i may have done something wrong.I measured my rifle by using a fired case neck sized and the the neck slotted with hacksaw blade and the pushing the bullet in by driving the bolt home hence pushing bullet to correct length,i did this several times and came out with very close readings and a good average.Any help would be appreciated

Try chambering a case with no bullet in it. If it's still tight, it's probably because it needs to be trimmed.

If you're trying to crimp the bullets (or crimping them accidentally when seating them) you can put a little bulge in the body of the case that will prevent easy chambering. I, by the way, would not crimp 22-250 bullets and if I did, I would use a Lee factory crimp die that would not cause any wrinkles in the case.

If it's none of the above, try seating the bullet a little deeper and see if that makes a difference.

The "strange letters" you're referring to are SAMI (an organization that sets standards for cartridge dimensions and pressures). The overall length of a cartridge is not set in stone. Generally (one exception being Barnes bullets) you get best accuracy by seating a bullet almost touching the rifling lands but many times, the cartridge will have to be shorter to feed through a magazine.

If a bullet is seated deeper than usual, the pressure in the cartridge will be higher which isn't a problem if the powder charge is reduced a bit. If it's seated to a longer overall length, the pressure will tend to be lower EXCEPT when the bullet is actually engaged in the lands in which case the presure may be higher. In a cartridge case the size of a 22-250 and larger, a little variation in length won't make much of a difference unless you're getting up toward a maximum load.

Out of my SAKO 22-250 varmiter my OAL is 2.380 so I'd guess that full length resizing of cases every now and then would take care of the hard bolt closing problem. 2.5" does seem a little bit long though. Chamber a bullet and see if the rifling is engaging the bullet and how much.

Color the bullet ogive with magic marker and check for rifleing marks after chambering it. The ink will show if the bullet is contacting the lead or not.

How many times has the batch of cases been loaded? They may need trimming.
Have you lubed the inside of the necks when sizeing? If not the expander ball may have pulled the shoulder out a touch causing your resistance.
These are cases fired in your rifle and not "range brass" right? Sometimes cases fired in other rifles don`t want to fit another chamber easily even though they have been full sized.

The SAAMI max COL in the manuals is usually the lenght that will fit in any magazine of a rifle factory chambered for that cartridge. It isn`t always the max that will fit the chamber. You can have a cartridge that won`t fit in your rifles magazine but chambers and fires just fine, especially long plastic tipped type bullets that always seem to need to be seated long to get anywhere near the rifleing. The Nosler BT, Hornady SST, ect are examples.