i ordered a 260 from DPMS last summer. it took almost 9 months to get here. Granted it was a bit special with heavy fluted SS barrel (blackened flutes) JP trigger and gas block, special stock etc. but my dealer kept getting a run around from them as to when it would be done. In anycase it finally got here this spring, The first groups were outstanding, less than 3/4". but since then it keeps deteriorating. Doesn't matter what load i use the groupls just keep getting bigger. last one was over 14"@200. Only thing i can think of is that in the fluting sequence the barrel got over stressed. Sent it back to DPMS, now to see how long it will take to get back.

When you do get it back and try it out please post what you find.

Interesting problem. I have a Springfield M1A that shot under an inch when knew but within 500 rds was doing 6 inches. I sent it back and they replaced the bolt and now it shoots great again.

With most semi-automatics, there is so much stuff attached to the barrel that if something loosens up it can play havoc with accuracy.

With a M1-A or an AR type rifle, others as well, build up in the gas tube, gas system can change vibrations and again effect accuracy.

Also with the M1-A bedding can go bad.

[Let the record reflect that none of things effect a H&K, as nothing is attached to the barrel, no gas system, and there is no bedding to go bad . ]

If a rifle is set up "right", these things should not happen, at least for the life of the barrel.