OK, let's look at the other end of the case. What you describe is symptomatic of excessive chamber pressure, which is unlikely in a factory load and factory chambered barrel, but you need to do some digging - clean the weapon.
1. Look at the casehead - Is the face burnished or flattened, or do the headstamp characters look thinner compared to the out-of-the-box round? Is the area just around the primer pocket shiny? Is there a significant indent from the extractor into the extractor groove? Is the bolt difficult to rotate/extract after firing? If one or in combination, you may have pressure problems.
2. If you suspect high pressure, then look for cause - Does the out-of-the-box round chamber easily? If not, look for interference on the case shoulder, case neck, neck mouth - this can be done by applying a very light coat of your wife's favorite lipstick, just enough to see a film, on the entire round, chamber once and extract, and look for spots where it's clean. If the round is too tight to the shoulder, too tight to the neck, or if the projectile is being pushed back into the neck on chambering, you can get high pressure. This will cause the unsupported case head to swell into the bolt face (hence the burnish/polish marks and flattened headstamp) and to expand in diameter. Check the head diameter at the rim and just in front of the extractor groove from an unfired lot against the once-fired. If the head expansion is more than .0010" (.0005" preferred), indications are pressure problems.
3. Obtain a headspace gage and check the weapon's headspace to SAAMI standards.
4. Slug the bore and measure, once at the throat, and once at the muzzle. Compare to SAAMI specs. Overtight bores raise pressure.
5. Get a chamber cast using Cerrosafe. Measure the chamber against SAAMI specs. Remember to measure the Cerrosafe right after knocking out the cast, as it expands a bit with age.
6. Try a different lot from Winchester and another mfr if avaliable, and do all of the measurements and trials on these in #2 before firing any rounds. Record results and observations. If your weapon is within spec limits for the bore diameters (lands and grooves) and chambered properly, contact Winchester with your data and see what they have to say. If the weapon does not meet spec, contact the mfr and ask why.