Two citizen initiative campaign submitted boxloads of petitions by the Friday deadline, and both appear to have an excellent shot at making the statewide ballot this fall.

Tim Eyman, the state’s most prominent use of the initiative process, turned in what he and co-sponsors Jack and Mike Fagan estimated at at least 334,000 signatures for their Initiative 1366. That measure would direct the Legislature to place a constitutional amendment on the 2016 ballot for ratification — or face a 1-cent reduction in the state’s 6.5-cent sales tax.

The State Supreme Court previously overturned an earlier Eyman initiative to require a two-thirds vote  in both houses to approve tax hikes in Olympia. The only way to overcome that ruling would be to amend the state Constitution. Voters can’t amend by initiative; it must originate in the Legislature, with two-thirds votes in both chambers.  I-1366 would provide an incentive — a potential $1 billion annual revenue loss — for lawmakers to place it on the ballot.

The other measure, Initiative 1401, is backed by billionaire Microsoft co-founder and Seahawks owner Paul Allen. It would expand state authority over combatting trafficking of endangered species and their parts. It would make selling, purchasing, trading, or distributing endangered animals and products containing such species, a gross misdemeanor or class-C felony, with exemptions for certain types of transfers.

Their backers brought in an estimated 349,000 signatures on Wednesday.

If history is a guide, both measures are likely to make the fall ballot. The bare minimum is 246,372 valid signatures of registered Washington voters. To cover duplicates or invalid signatures, the state Elections Division always recommends submitting about 325,000 to be on the safe side.

Both sets of petitions will undergo a page-by-page inspection, including a preliminary fraud check, and then go to the State Archives for imaging. When images return, the Elections work crew will compile them into volumes and prepare for random-sampling of 3 percent of the signatures to see if they match those on file for registered voters. Actual scrutiny of the sample will begin about July 13 and should be complete by the week of the 20th.