[SgtStrafer]

In the reloading manual I have it shows a load that requires a magnum primer. If a load requires a regular primer can a magnum primer be used in its place?

 

[allconfederate]

Magnum Primer/Standard Primer

Most if not all load books will show what primer was used to develope their data. It is always a good practice to follow those guide lines that are published. I cannot endorse the practice of substituting Magnum primers in place of Standard primers as there could be a safety issue.

 

[robocop10mm]

mag primers

You can use the mag primer in place of the standard primer BUT, you must back off the load and work up with the new component. The mag primer is called for in the hard to ignite powders like W-296 and H-110. It will add a bit to the pressure so you have to work up a load just for it.

 

[allconfederate]

In the reloading manual I have it shows a load that requires a magnum primer. If a load requires a regular primer can a magnum primer be used in its place?

After rereading your post and answering exactly what you requested, the answer would be no, you should not substitute! Reducing your load as robocop10mm has posted would be appropiate, but what would be the advantage?
Data that is published has a built in safety for users and also liability issues. However, the people that are publishing this data worked up the said loads using the components listed, and determined that the primer used was adequate for the application. Using a Magnum primer in the place of a Standard primer has no benefit if you are seeking the performance from the data which was published in the first place.
Magnum and Standard primers are used for a particular reason when looking at powder burning rates, and by substituting you could very well be in the danger zone without knowing it. There are loading programs, such as Quick load that show pressure zones when using different components, and if you do plan on changing any component other than was listed, then you must take into consideration the composition of the components you are changing. In retrospect, published data is there for a reason, not only as fact of their findings, but the needed safety involved when loading your own cartridges.