142 F.3d 445
NOTICE: Ninth Circuit Rule 36-3 provides that dispositions other than opinions or orders designated for publication are not precedential and should not be cited except when relevant under the doctrines of law of the case, res judicata, or collateral estoppel.Ervin Charles St. AMAND, Plaintiff-Appellant,v.Ron ANGELONE, Director, NDPO;  Karl L. Sannicks, Asst. Dir.,NDPO;  George Deeds, Former Warden, SDCC;  Sherman Hatcher,Warden, SDCC;  Gary True, AWO;  Tom Smith, CCWS;  RuthRiley, CCWS;  Merline Willick;  Robin L. Bates, CCRM,Defendants-Appellees.
No. 97-15521.D.C. No. CV-95-00446-DWH.
United States Court of Appeals,Ninth Circuit.
Submitted April 20, 1998**.Decided April 22, 1998.

Appeal from the United States District Court for the District of Nevada David Warner Hagen, District Judge, Presiding.
Before BRUNETTI, RYMER, and T.G. NELSON, Circuit Judges.


1
MEMORANDUM*


2
Ervin Charles St. Amand, a former Nevada state prisoner, appeals pro se the district court's summary judgment for defendant prison officials in his 42 U.S.C. § 1983 action.  St. Amand alleges that defendants violated his constitutional rights by incorrectly calculating his work and education credits so that he was released from prison on September 30, 1993, rather than on April 14, 1993.  We have jurisdiction pursuant to 28 U.S.C. § 1291.  We review de novo, see Jesinger v. Nevada Fed.  Credit Union, 24 F.3d 1127, 1130 (9th Cir.1994), and we vacate and remand.


3
Because the allegations made in St. Amand's section 1983 complaint challenge the validity of his sentence, his section 1983 action is not cognizable.  See Heck v. Humphrey, 512 U.S. 477, 486-87, 114 S.Ct. 2364, 129 L.Ed.2d 383 (1994);  Preiser v. Rodriguez, 411 U.S. 475, 500, 93 S.Ct. 1827, 36 L.Ed.2d 439 (1973).  Further, because St. Amand's action is not cognizable, the district court should have dismissed St. Amand's action without prejudice.  See Trimble v. City of Santa Rosa, 49 F.3d 583, 585 (9th Cir.1995) (per curiam).  Accordingly, we vacate the district court's judgment and remand for the district court to enter judgment dismissing St. Amand's section 1983 action without prejudice.

VACATED and REMANDED.1


**
 The panel unanimously finds this case suitable for decision without oral argument.  See Fed.  R.App. P. 34(a);  9th Cir.  R. 34-4


*
 This disposition is not appropriate for publication and may not be cited to or by the courts of this circuit except as provided by 9th Cir.  R. 36-3


1
 St. Amand's request to file a late opening brief is denied as moot


