Hope this helps
Model 721 Description: First truly modern centerfire rifle with the strongest bolt ever developed. Offered in long action only. Introduction Year: 1948 Year Discontinued: 1962 Total Production: Approximately 118,000 Designer/Inventor: Merle "Mike" Walker & Homer W. Young Action Type: Bolt action Caliber/Gauge: .264 Win. – 1961 – 22" barrel
.270 Win. – 1948 – 24" & 22" barrel
.280 Rem. – 1961 – 22" barrel
.30-06 Sprg. - 1948 – 24" & 22" barrel
.300 H&H Mag – 1948 – 26" & 24" barrel Serial Number Blocks: 11,000 – 430,0000 Various Models: 721A 1948 – 1962
721AC 1949 – 1955
721B Special Grade 1949 – 1955
721D Peerless Grade 1949 – 1959
721F Premier Grade 1949 – 1959
Model 722
Description: First truly modern centerfire rifle with the strongest bolt ever developed. Offered in short action only.
Introduction Year: 1948
Year Discontinued: 1962
Total Production: Approximately 118,000
Designer/Inventor: Merle "Mike" Walker & Homer W. Young
Action Type: Bolt action
Caliber/Gauge: .222 Rem. - .1950 - 26" & 24" barrel
.222 Rem. Mag. - 1958 24" barrel
.243 Win. - 1959 - 22" barrel
.244 Rem. - 1956 24" & 22" barrel
.257 Roberts - 1948 - 24" & 22" barrel
.300 Savage - 1948 - 24" & 22" barrel
.308 Win. - 1956 - 24" & 22" barrel
Serial Number Blocks: 11,000 – 430,0000
Various Models: 722A - 1948-1962
722AC - 1949-1955
722B Special - 1949-1955
722 D Peerless - 1949-1959
722 F Premier - 1949-1959
722 ADL - 1955-1959
722 BDL - 1955-1959
Model 725 Description: Similar to the Models 721/722 with a Monte Carlo stock, Hinged floorplate and oversized three position safety. Introduction Year: 1958 Year Discontinued: 1961 Total Production: Approximately 17,000 Designer/Inventor: Wayne Leek & Charlie Campbell Action Type: Bolt action Caliber/Gauge: .270 Win – 1958 – 22" barrel
.280 Rem. – 1958 – 22" barrel
.30-06 Sprg. – 1958 – 22" barrel
.222 Rem. – 1959 – 24" barrel
.243 Win. – 1960 – 22" barrel
.244 Rem. – 1959 – 22" barrel
.375 H&H Mag – 1960 – 26" barrel
.458 Win. Mag – 1960 – 26" barrel Serial Number Blocks: 700,000 – 717,000 Various Models: 725ADL – 1958
725 Kodiak – Custom Shop - 1961
725D Peerless – Custom Shop – 1961
725F Premier – Customer Shop -1961
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All the model 721/722 with the 22" barrels if you do a search are whats called the "transition" models when they made the model 725 they also started making 22" barrels for the 721/722. According to the code dates my 722 222mag was made 1960 .