I have a Rem SPS in 300 ultra mag,the SPS comes with a limbsaver.Makes a big diff.My son has a 338 Ultra mag we just put one on it and diff.is like nite and day.SIR has them in stock so does Wholesale Sports,well worth the money.I have a pac.dec. on my 358 Norma and I don't think it works as well as the limbsaver.